diff --git a/.changes/unreleased/DX-20230607-130344.yaml b/.changes/unreleased/DX-20230607-130344.yaml
new file mode 100644
index 000000000..c7774c395
--- /dev/null
+++ b/.changes/unreleased/DX-20230607-130344.yaml
@@ -0,0 +1,6 @@
+kind: DX
+body: Add methods to RegroupmentRepository and fullfill Center / Regroupment Doctrine
+  mapping
+time: 2023-06-07T13:03:44.177864269+02:00
+custom:
+  Issue: ""
diff --git a/src/Bundle/ChillMainBundle/Entity/Center.php b/src/Bundle/ChillMainBundle/Entity/Center.php
index 5ca051ec0..0d5402409 100644
--- a/src/Bundle/ChillMainBundle/Entity/Center.php
+++ b/src/Bundle/ChillMainBundle/Entity/Center.php
@@ -48,12 +48,19 @@ class Center implements HasCenterInterface
      */
     private string $name = '';
 
+    /**
+     * @var Collection<Regroupment>
+     * @ORM\ManyToMany(targetEntity=Regroupment::class, mappedBy="centers")
+     */
+    private Collection $regroupments;
+
     /**
      * Center constructor.
      */
     public function __construct()
     {
-        $this->groupCenters = new \Doctrine\Common\Collections\ArrayCollection();
+        $this->groupCenters = new ArrayCollection();
+        $this->regroupments = new ArrayCollection();
     }
 
     /**
@@ -106,6 +113,14 @@ class Center implements HasCenterInterface
         return $this->name;
     }
 
+    /**
+     * @return Collection<Regroupment>
+     */
+    public function getRegroupments(): Collection
+    {
+        return $this->regroupments;
+    }
+
     /**
      * @param $name
      *
diff --git a/src/Bundle/ChillMainBundle/Entity/Regroupment.php b/src/Bundle/ChillMainBundle/Entity/Regroupment.php
index 96953abf5..c5d9525cf 100644
--- a/src/Bundle/ChillMainBundle/Entity/Regroupment.php
+++ b/src/Bundle/ChillMainBundle/Entity/Regroupment.php
@@ -22,11 +22,12 @@ use Doctrine\ORM\Mapping as ORM;
 class Regroupment
 {
     /**
-     * @var Center
      * @ORM\ManyToMany(
-     *     targetEntity=Center::class
+     *     targetEntity=Center::class,
+     *     inversedBy="regroupments"
      * )
      * @ORM\Id
+     * @var Collection<Center>
      */
     private Collection $centers;
 
@@ -52,6 +53,26 @@ class Regroupment
         $this->centers = new ArrayCollection();
     }
 
+    public function addCenter(Center $center): self
+    {
+        if (!$this->centers->contains($center)) {
+            $this->centers->add($center);
+            $center->getRegroupments()->add($this);
+        }
+
+        return $this;
+    }
+
+    public function removeCenter(Center $center): self
+    {
+        if ($this->centers->contains($center)) {
+            $this->centers->removeElement($center);
+            $center->getRegroupments()->removeElement($this);
+        }
+
+        return $this;
+    }
+
     public function getCenters(): Collection
     {
         return $this->centers;
diff --git a/src/Bundle/ChillMainBundle/Form/RegroupmentType.php b/src/Bundle/ChillMainBundle/Form/RegroupmentType.php
index bc8e6684f..22814598a 100644
--- a/src/Bundle/ChillMainBundle/Form/RegroupmentType.php
+++ b/src/Bundle/ChillMainBundle/Form/RegroupmentType.php
@@ -31,7 +31,7 @@ class RegroupmentType extends AbstractType
             ->add('centers', EntityType::class, [
                 'class' => Center::class,
                 'multiple' => true,
-                'attr' => ['class' => 'select2'],
+                'expanded' => true,
             ])
             ->add('isActive', CheckboxType::class, [
                 'label' => 'Actif ?',
diff --git a/src/Bundle/ChillMainBundle/Repository/RegroupmentRepository.php b/src/Bundle/ChillMainBundle/Repository/RegroupmentRepository.php
index a28f2f341..c115d5d98 100644
--- a/src/Bundle/ChillMainBundle/Repository/RegroupmentRepository.php
+++ b/src/Bundle/ChillMainBundle/Repository/RegroupmentRepository.php
@@ -14,6 +14,8 @@ namespace Chill\MainBundle\Repository;
 use Chill\MainBundle\Entity\Regroupment;
 use Doctrine\ORM\EntityManagerInterface;
 use Doctrine\ORM\EntityRepository;
+use Doctrine\ORM\NonUniqueResultException;
+use Doctrine\ORM\NoResultException;
 use Doctrine\Persistence\ObjectRepository;
 
 final class RegroupmentRepository implements ObjectRepository
@@ -59,6 +61,30 @@ final class RegroupmentRepository implements ObjectRepository
         return $this->repository->findOneBy($criteria, $orderBy);
     }
 
+    /**
+     * @throws NonUniqueResultException
+     * @throws NoResultException
+     */
+    public function findOneByName(string $name): ?Regroupment
+    {
+        return $this->repository->createQueryBuilder('r')
+            ->where('LOWER(r.name) = LOWER(:searched)')
+            ->setParameter('searched', $name)
+            ->getQuery()
+            ->getSingleResult();
+    }
+
+    /**
+     * @return array<Regroupment>
+     */
+    public function findRegroupmentAssociatedToNoCenter(): array
+    {
+        return $this->repository->createQueryBuilder('r')
+            ->where('SIZE(r.centers) = 0')
+            ->getQuery()
+            ->getResult();
+    }
+
     public function getClassName()
     {
         return Regroupment::class;