diff --git a/src/Bundle/ChillMainBundle/Resources/views/CRUD/_view_content.html.twig b/src/Bundle/ChillMainBundle/Resources/views/CRUD/_view_content.html.twig
index 203a24926..7d0023a39 100644
--- a/src/Bundle/ChillMainBundle/Resources/views/CRUD/_view_content.html.twig
+++ b/src/Bundle/ChillMainBundle/Resources/views/CRUD/_view_content.html.twig
@@ -4,7 +4,7 @@
     {% endblock crud_content_header %}
 
     {% block crud_content_view %}
-        
+
         {% block crud_content_view_details %}
             <dl class="chill_view_data">
                 <dt>id</dt>
@@ -20,7 +20,7 @@
                         {{ 'Cancel'|trans }}
                     </a>
                 </li>
-            {% endblock %} 
+            {% endblock %}
             {% block content_view_actions_before %}{% endblock %}
             {% block content_form_actions_delete %}
                 {% if chill_crud_action_exists(crud_name, 'delete') %}
@@ -32,7 +32,7 @@
                 </li>
                 {% endif %}
                 {% endif %}
-            {% endblock content_form_actions_delete %} 
+            {% endblock content_form_actions_delete %}
             {% block content_view_actions_duplicate_link %}
                 {% if chill_crud_action_exists(crud_name, 'new') %}
                 {% if is_granted(chill_crud_config('role', crud_name, 'new'), entity) %}
@@ -44,6 +44,14 @@
                 {% endif %}
                 {% endif %}
             {% endblock content_view_actions_duplicate_link %}
+            {% block content_view_actions_merge %}
+                <li>
+                    <a href="{{ chill_path_add_return_path('chill_thirdparty_find_duplicate',
+                        { 'thirdparty_id': entity.id }) }}"
+                       title="{{ 'thirdparty_duplicate.merge'|trans }}"
+                       class="btn btn-misc">{{ 'thirdparty_duplicate.merge'|trans }}</a>
+                </li>
+            {% endblock %}
             {% block content_view_actions_edit_link %}
                 {% if chill_crud_action_exists(crud_name, 'edit') %}
                 {% if is_granted(chill_crud_config('role', crud_name, 'edit'), entity) %}
diff --git a/src/Bundle/ChillThirdPartyBundle/Controller/ThirdpartyDuplicateController.php b/src/Bundle/ChillThirdPartyBundle/Controller/ThirdpartyDuplicateController.php
index 5bcb52db0..a7fb87458 100644
--- a/src/Bundle/ChillThirdPartyBundle/Controller/ThirdpartyDuplicateController.php
+++ b/src/Bundle/ChillThirdPartyBundle/Controller/ThirdpartyDuplicateController.php
@@ -1,10 +1,106 @@
 <?php
 
+declare(strict_types=1);
+
+/*
+ * Chill is a software for social workers
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
 namespace Chill\ThirdPartyBundle\Controller;
 
+use Chill\PersonBundle\Form\PersonConfimDuplicateType;
+use Chill\ThirdPartyBundle\Form\ThirdpartyFindDuplicateType;
+use Chill\ThirdPartyBundle\Repository\ThirdPartyRepository;
+use Chill\ThirdPartyBundle\Service\ThirdpartyMergeService;
 use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\Routing\Annotation\Route;
 
 class ThirdpartyDuplicateController extends AbstractController
 {
+    public function __construct(private ThirdPartyRepository $thirdPartyRepository, private ThirdpartyMergeService $thirdPartyMergeService) {}
 
+    #[Route(path: '/{_locale}/3party/{thirdparty_id}/find-manually', name: 'chill_thirdparty_find_duplicate')]
+    public function findManuallyDuplicateAction(mixed $thirdparty_id, Request $request)
+    {
+        $thirdparty = $this->thirdPartyRepository->find($thirdparty_id);
+        dump($thirdparty_id);
+        dump($thirdparty);
+
+        if (null === $thirdparty) {
+            throw $this->createNotFoundException("Thirdparty with id {$thirdparty_id} not".' found on this server');
+        }
+
+        $form = $this->createForm(ThirdpartyFindDuplicateType::class);
+
+        $form->handleRequest($request);
+
+        if ($form->isSubmitted() && $form->isValid()) {
+            $thirdparty2 = $form->get('thirdparty')->getData();
+
+            if (null === $thirdparty2) {
+                throw $this->createNotFoundException("Thirdparty with id {$thirdparty2->getId}() not".' found on this server');
+            }
+
+            $direction = $form->get('direction')->getData();
+
+            if ('starting' === $direction) {
+                $params = [
+                    'thirdparty1_id' => $thirdparty->getId(),
+                    'thirdparty2_id' => $thirdparty2->getId(),
+                ];
+            } else {
+                $params = [
+                    'thirdparty1_id' => $thirdparty2->getId(),
+                    'thirdparty2_id' => $thirdparty->getId(),
+                ];
+            }
+
+            return $this->redirectToRoute('chill_thirdparty_duplicate_confirm', $params);
+        }
+
+        return $this->render('@ChillThirdParty/ThirdPartyDuplicate/find_duplicate.html.twig', [
+            'thirdparty' => $thirdparty,
+            'form' => $form->createView(),
+        ]);
+    }
+
+    #[Route(path: '/{_locale}/3party/{thirdparty1_id}/duplicate/{thirdparty2_id}/confirm', name: 'chill_thirdparty_duplicate_confirm')]
+    public function confirmAction(mixed $thirdparty1_id, mixed $thirdparty2_id, Request $request)
+    {
+        if ($thirdparty1_id === $thirdparty2_id) {
+            throw new \InvalidArgumentException('Can not merge same thirdparty');
+        }
+
+        $thirdparty1 = $this->thirdPartyRepository->find($thirdparty1_id);
+        $thirdparty2 = $this->thirdPartyRepository->find($thirdparty2_id);
+
+        if (null === $thirdparty1) {
+            throw $this->createNotFoundException("Thirdparty with id {$thirdparty1_id} not".' found on this server');
+        }
+
+        if (null === $thirdparty2) {
+            throw $this->createNotFoundException("Person with id {$thirdparty2_id} not".' found on this server');
+        }
+
+        $form = $this->createForm(PersonConfimDuplicateType::class);
+
+        $form->handleRequest($request);
+
+        if ($form->isSubmitted() && $form->isValid()) {
+
+            $this->thirdPartyMergeService->merge($thirdparty1, $thirdparty2);
+
+            return $this->redirectToRoute('chill_crud_3party_3party_view', ['id' => $thirdparty1->getId()]);
+        }
+
+        return $this->render('@ChillThirdParty/ThirdPartyDuplicate/confirm.html.twig', [
+            'thirdparty' => $thirdparty1,
+            'thirdparty2' => $thirdparty2,
+            'form' => $form->createView(),
+        ]);
+    }
 }
diff --git a/src/Bundle/ChillThirdPartyBundle/Form/ThirdpartyFindDuplicateType.php b/src/Bundle/ChillThirdPartyBundle/Form/ThirdpartyFindDuplicateType.php
new file mode 100644
index 000000000..8b2534bca
--- /dev/null
+++ b/src/Bundle/ChillThirdPartyBundle/Form/ThirdpartyFindDuplicateType.php
@@ -0,0 +1,32 @@
+<?php
+
+namespace Chill\ThirdPartyBundle\Form;
+
+use Chill\ThirdPartyBundle\Form\Type\PickThirdpartyDynamicType;
+use Symfony\Component\Form\AbstractType;
+use Symfony\Component\Form\Extension\Core\Type\HiddenType;
+use Symfony\Component\Form\FormBuilderInterface;
+
+class ThirdpartyFindDuplicateType extends AbstractType
+{
+    public function buildForm(FormBuilderInterface $builder, array $options)
+    {
+        $builder
+            ->add('thirdparty', PickThirdpartyDynamicType::class, [
+                'label' => 'Find duplicate',
+                'mapped' => false,
+            ])
+            ->add('direction', HiddenType::class, [
+                'data' => 'starting',
+            ]);
+    }
+
+    /**
+     * @return string
+     */
+    public function getBlockPrefix()
+    {
+        return 'chill_thirdpartybundle_thirdparty_find_manually_duplicate';
+    }
+
+}
diff --git a/src/Bundle/ChillThirdPartyBundle/Resources/views/ThirdPartyDuplicate/_details.html.twig b/src/Bundle/ChillThirdPartyBundle/Resources/views/ThirdPartyDuplicate/_details.html.twig
new file mode 100644
index 000000000..8896c8deb
--- /dev/null
+++ b/src/Bundle/ChillThirdPartyBundle/Resources/views/ThirdPartyDuplicate/_details.html.twig
@@ -0,0 +1,39 @@
+{%- macro details(thirdparty, options) -%}
+
+    <ul>
+        <li><b>{{ 'name'|trans }}</b>:
+            {{ thirdparty.name }}</li>
+        <li><b>{{ 'firstName'|trans }}</b>:
+            {% if thirdparty.firstname %}{{ thirdparty.firstname }}{% endif %}</li>
+        <li><b>{{ 'thirdparty.Civility'|trans }}</b>:
+            {% if thirdparty.getCivility %}{{ thirdparty.getCivility.name|localize_translatable_string }}{% endif %}</li>
+        <li><b>{{ 'thirdparty.NameCompany'|trans }}</b>:
+            {% if thirdparty.nameCompany is not empty %}{{ thirdparty.nameCompany }}{% endif %}</li>
+        <li><b>{{ 'thirdparty.Acronym'|trans }}</b>:
+            {% if thirdparty.acronym %}{{ thirdparty.acronym }}{% endif %}</li>
+        <li><b>{{ 'thirdparty.Profession'|trans }}</b>:
+            {% if thirdparty.profession %}{{ thirdparty.profession }}{% endif %}</li>
+        <li><b>{{ 'telephone'|trans }}</b>:
+            {% if thirdparty.telephone %}{{ thirdparty.telephone }}{% endif %}</li>
+        <li><b>{{ 'email'|trans }}</b>:
+            {% if thirdparty.email is not null %}{{ thirdparty.email }}{% endif %}</li>
+        <li><b>{{ 'address'|trans }}</b>:
+            {%- if thirdparty.getAddress is not empty -%}
+                {{ thirdparty.getAddress|chill_entity_render_box }}
+            {% endif %}</li>
+        <li><b>{{ 'thirdparty.Contact data are confidential'|trans }}</b>:
+            {{ thirdparty.contactDataAnonymous }}</li>
+    </ul>
+{% endmacro %}
+
+{#{%- macro links(thirdparty, options) -%}#}
+{#    <ul>#}
+{##}
+{#        <li><b>{{ person.counters.nb_activity }}</b> {{ (person.counters.nb_activity > 1)? 'échanges' : 'échange' }}</li>#}
+{#        <li><b>{{ person.counters.nb_task }}</b> {{ (person.counters.nb_task > 1)? 'tâches' : 'tâche' }}</li>#}
+{#        <li><b>{{ person.counters.nb_document }}</b> {{ (person.counters.nb_document > 1)? 'documents' : 'document' }}</li>#}
+{#            <li><b>{{ person.counters.nb_event }}</b> {{ (person.counters.nb_event > 1)? 'événements' : 'événement' }}</li>#}
+{#        <li><b>{{ person.counters.nb_addresses }}</b> {{ (person.counters.nb_addresses > 1)? 'adresses' : 'adresse' }}</li>#}
+{##}
+{#    </ul>#}
+{#{% endmacro %}#}
diff --git a/src/Bundle/ChillThirdPartyBundle/Resources/views/ThirdPartyDuplicate/confirm.html.twig b/src/Bundle/ChillThirdPartyBundle/Resources/views/ThirdPartyDuplicate/confirm.html.twig
new file mode 100644
index 000000000..4baa4552e
--- /dev/null
+++ b/src/Bundle/ChillThirdPartyBundle/Resources/views/ThirdPartyDuplicate/confirm.html.twig
@@ -0,0 +1,97 @@
+{% extends "@ChillMain/layout.html.twig"  %}
+
+{% import '@ChillThirdParty/ThirdPartyDuplicate/_details.html.twig' as details %}
+
+{% block title %}{{ 'thirdparty_duplicate.Thirdparty duplicate title'|trans ~ ' ' ~ thirdparty.name }}{% endblock %}
+
+{% block content %}
+    <style>
+        div.duplicate-content {
+            margin: 0 2rem;
+        }
+        div.col {
+            padding: 1em;
+            border: 3px solid #cccccc;
+        }
+        div.border {
+            border: 4px solid #3c9f8d;
+        }
+
+
+    </style>
+    <div class="container-fluid content"><div class="duplicate-content">
+
+            <h1>{{ 'thirdparty_duplicate.Merge duplicate thirdparties'|trans }}</h1>
+
+            <div class="col-md-11">
+                <p><b>{{ 'thirdparty_duplicate.Thirdparty to delete'|trans }}</b>:
+                    {{ 'thirdparty_duplicate.Thirdparty to delete explanation'|trans }}
+                </p>
+                <div class="col">
+
+                    <h1><span><a class="btn btn-show" target="_blank" title="{{ 'Open in another window'|trans }}" href="{{ path('chill_crud_3party_3party_view', { id : thirdparty2.id }) }}"></a></span>
+                        {{ thirdparty2 }}
+                    </h1>
+
+                    <h4>{{ 'Deleted datas'|trans ~ ':' }}</h4>
+                    {{ details.details(thirdparty2) }}
+
+{#                    <h4>{{ 'Moved links'|trans ~ ':' }}</h4>#}
+{#                    {{ details.links(thirdparty2) }}#}
+                </div>
+            </div>
+
+            <div class="col-md-11">
+                <p><b>{{ 'thirdparty_duplicate.Thirdparty to keep'|trans }}</b>:
+                    {{ 'thirdparty_duplicate.Thirdparty to delete explanation'|trans }}
+                </p>
+                <div class="col border">
+
+                    <h1><span><a class="btn btn-show" target="_blank" title="{{ 'Open in another window'|trans }}" href="{{ path('chill_crud_3party_3party_view', { id : thirdparty.id }) }}"></a></span>
+                        {{ thirdparty }}
+                    </h1>
+
+                    <h4>{{ 'thirdparty_duplicate.data to keep'|trans ~ ':' }}</h4>
+                    {{ details.details(thirdparty) }}
+
+{#                    <h4>{{ 'thirdparty_duplicate.links to keep'|trans ~ ':' }}</h4>#}
+{#                    {{ sidepane.links(thirdparty) }}#}
+                </div>
+            </div>
+
+            {{ form_start(form) }}
+
+            <div class="col-md-12 centered">
+
+                <div class="container-fluid" style="padding-top: 1em;">
+                    <div class="clear" style="padding-top: 10px;">
+                        {{ form_widget(form.confirm) }}
+                    </div>
+                    <div class="col-11">
+                        {{ form_label(form.confirm) }}
+                    </div>
+                </div>
+            </div>
+
+            <ul class="col-12 record_actions">
+                <li class="cancel">
+                    <a href="{{ path('chill_thirdparty_find_duplicate', {thirdparty_id : thirdparty.id}) }}" class="btn btn-chill-gray center margin-5">
+                        {{ 'Return'|trans }}
+                    </a>
+                </li>
+                <li class="cancel">
+                    <a  href="{{ path('chill_thirdparty_duplicate_confirm', { thirdparty1_id : thirdparty2.id, thirdparty2_id : thirdparty.id }) }}"
+                        class="btn btn-action">
+                        <i class="fa fa-exchange"></i>
+                        {{ 'Invert'|trans }}
+                    </a>
+                </li>
+                <li>
+                    <button class="btn btn-submit" type="submit"><i class="fa fa-cog fa-fw"></i>{{ 'Merge'|trans }}</button>
+                </li>
+            </ul>
+
+            {{ form_end(form) }}
+
+        </div></div>
+{% endblock %}
diff --git a/src/Bundle/ChillThirdPartyBundle/Resources/views/ThirdPartyDuplicate/find_duplicate.html.twig b/src/Bundle/ChillThirdPartyBundle/Resources/views/ThirdPartyDuplicate/find_duplicate.html.twig
new file mode 100644
index 000000000..9dd1a0992
--- /dev/null
+++ b/src/Bundle/ChillThirdPartyBundle/Resources/views/ThirdPartyDuplicate/find_duplicate.html.twig
@@ -0,0 +1,38 @@
+{% extends "@ChillMain/layout.html.twig"  %}
+
+{% set activeRouteKey = 'chill_thirdparty_duplicate' %}
+
+{% block title %}{{ 'Find duplicate'|trans ~ ' ' ~ thirdparty.name|capitalize }}{% endblock %}
+
+
+{% block content %}
+    <div class="person-duplicate">
+
+        <h1>{{ 'find duplicate thirdparty'|trans }}</h1>
+
+        {{ form_start(form) }}
+        {{ form_rest(form) }}
+
+        <ul class="record_actions sticky-form-buttons">
+            <li class="cancel">
+                <a href="{{ path('chill_crud_3party_3party_view',  {'id' : thirdparty.id}) }}" class="btn btn-cancel">
+                    {{ 'Return'|trans }}
+                </a>
+            </li>
+            <li>
+                <button class="btn btn-save" type="submit">{{ 'Next'|trans }}</button>
+            </li>
+        </ul>
+
+        {{ form_end(form) }}
+
+    </div>
+{% endblock %}
+
+{% block js %}
+    {{ encore_entry_script_tags('mod_pickentity_type') }}
+{% endblock %}
+
+{% block css %}
+    {{ encore_entry_link_tags('mod_pickentity_type') }}
+{% endblock %}
diff --git a/src/Bundle/ChillThirdPartyBundle/translations/messages.fr.yml b/src/Bundle/ChillThirdPartyBundle/translations/messages.fr.yml
index 52bae6fee..9432fbdc0 100644
--- a/src/Bundle/ChillThirdPartyBundle/translations/messages.fr.yml
+++ b/src/Bundle/ChillThirdPartyBundle/translations/messages.fr.yml
@@ -133,6 +133,7 @@ is thirdparty: Le demandeur est un tiers
 
 Filter by person's who have a residential address located at a thirdparty of type: Filtrer les usagers qui ont une addresse de résidence chez un tiers
 "Filtered by person's who have a residential address located at a thirdparty of type %thirdparty_type% and valid on %date_calc%": "Uniquement les usagers qui ont une addresse de résidence chez un tiers de catégorie %thirdparty_type% et valide sur la date %date_calc%"
+find duplicate thirdparty: 'Désigner un tier doublon'
 
 
 # admin