diff --git a/src/EventListener/UniqueDefaultWorkflowListener.php b/src/EventListener/UniqueDefaultWorkflowListener.php
new file mode 100644
index 0000000..15b61c4
--- /dev/null
+++ b/src/EventListener/UniqueDefaultWorkflowListener.php
@@ -0,0 +1,46 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\EventListener;
+
+use App\Entity\Workflow;
+use Doctrine\Bundle\DoctrineBundle\Attribute\AsDoctrineListener;
+use Doctrine\ORM\Event\OnFlushEventArgs;
+use Doctrine\ORM\Events;
+
+#[AsDoctrineListener(event: Events::onFlush)]
+final class UniqueDefaultWorkflowListener
+{
+    public function onFlush(OnFlushEventArgs $args): void
+    {
+        $em  = $args->getObjectManager();
+        $uow = $em->getUnitOfWork();
+
+        $candidates = [];
+        foreach ($uow->getScheduledEntityInsertions() as $entity) {
+            if ($entity instanceof Workflow && $entity->isDefault()) {
+                $candidates[] = $entity;
+            }
+        }
+        foreach ($uow->getScheduledEntityUpdates() as $entity) {
+            if ($entity instanceof Workflow && $entity->isDefault()) {
+                $candidates[] = $entity;
+            }
+        }
+
+        if (0 === count($candidates)) {
+            return;
+        }
+
+        $metadata = $em->getClassMetadata(Workflow::class);
+        $repo     = $em->getRepository(Workflow::class);
+        foreach ($repo->findBy(['isDefault' => true]) as $existing) {
+            if (in_array($existing, $candidates, true)) {
+                continue;
+            }
+            $existing->setIsDefault(false);
+            $uow->recomputeSingleEntityChangeSet($metadata, $existing);
+        }
+    }
+}