diff --git a/src/Bundle/ChillMainBundle/Entity/Workflow/EntityWorkflowStep.php b/src/Bundle/ChillMainBundle/Entity/Workflow/EntityWorkflowStep.php
index e43d524a4..39729aa96 100644
--- a/src/Bundle/ChillMainBundle/Entity/Workflow/EntityWorkflowStep.php
+++ b/src/Bundle/ChillMainBundle/Entity/Workflow/EntityWorkflowStep.php
@@ -12,6 +12,7 @@ declare(strict_types=1);
 namespace Chill\MainBundle\Entity\Workflow;
 
 use Chill\MainBundle\Entity\User;
+use Chill\MainBundle\Validator\Constraints\Entity\WorkflowStepUsers;
 use DateTimeImmutable;
 use Doctrine\Common\Collections\ArrayCollection;
 use Doctrine\Common\Collections\Collection;
@@ -24,6 +25,7 @@ use function in_array;
 /**
  * @ORM\Entity
  * @ORM\Table("chill_main_workflow_entity_step")
+ * @WorkflowStepUsers()
  */
 class EntityWorkflowStep
 {
diff --git a/src/Bundle/ChillMainBundle/Validator/Constraints/Entity/WorkflowStepUsers.php b/src/Bundle/ChillMainBundle/Validator/Constraints/Entity/WorkflowStepUsers.php
new file mode 100644
index 000000000..842df37cf
--- /dev/null
+++ b/src/Bundle/ChillMainBundle/Validator/Constraints/Entity/WorkflowStepUsers.php
@@ -0,0 +1,27 @@
+<?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\MainBundle\Validator\Constraints\Entity;
+
+use Symfony\Component\Validator\Constraint;
+
+/**
+ * @Annotation
+ */
+class WorkflowStepUsers extends Constraint
+{
+    public string $message = 'The user in cc cannot be a dest user in the same workflow step';
+
+    public function getTargets()
+    {
+        return [self::CLASS_CONSTRAINT];
+    }
+}
diff --git a/src/Bundle/ChillMainBundle/Validator/Constraints/Entity/WorkflowStepUsersValidator.php b/src/Bundle/ChillMainBundle/Validator/Constraints/Entity/WorkflowStepUsersValidator.php
new file mode 100644
index 000000000..9f3684575
--- /dev/null
+++ b/src/Bundle/ChillMainBundle/Validator/Constraints/Entity/WorkflowStepUsersValidator.php
@@ -0,0 +1,43 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * Chill is a software for social workers
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace Chill\MainBundle\Validator\Constraints\Entity;
+
+use Chill\MainBundle\Entity\Workflow\EntityWorkflowStep;
+use Symfony\Component\Form\Exception\UnexpectedTypeException;
+use Symfony\Component\Validator\Constraint;
+use Symfony\Component\Validator\ConstraintValidator;
+
+/**
+ * @Annotation
+ */
+class WorkflowStepUsersValidator extends ConstraintValidator
+{
+    public function validate($value, Constraint $constraint)
+    {
+        if (!$value instanceof EntityWorkflowStep) {
+            throw new UnexpectedTypeException($value, EntityWorkflowStep::class);
+        }
+
+        if (!$constraint instanceof WorkflowStepUsers) {
+            throw new UnexpectedTypeException($constraint, WorkflowStepUsers::class);
+        }
+
+        foreach($value->getCcUser() as $u) {
+            if ($value->getCcUser()->contains($u)) {
+                $this->context
+                    ->buildViolation($constraint->message)
+                    ->atPath('ccUsers')
+                    ->addViolation();
+            }
+        }
+    }
+}