diff --git a/CHANGES.rst b/CHANGES.rst
index d0b5147..89ccdd2 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -5,6 +5,9 @@ Changelog
 1.2.27 (unreleased)
 -------------------
 
+- CITIBDC-568 : Allow non-ASCII characters in schedule comments by overriding DictFieldDeserializer for ISchedule fields.
+  [remdub]
+
 - Fix CSRF error : Wrong factory! Should be ContactCategoriesVocabularyFactory() instead of ContactCategoriesDe...
   [boulch]
 
diff --git a/src/imio/directory/core/contents/contact/configure.zcml b/src/imio/directory/core/contents/contact/configure.zcml
index be18735..0093d4f 100644
--- a/src/imio/directory/core/contents/contact/configure.zcml
+++ b/src/imio/directory/core/contents/contact/configure.zcml
@@ -6,6 +6,7 @@
            for=".content.IContact plone.restapi.interfaces.IPloneRestapiLayer" />
 
   <adapter factory=".serializer.ContactJSONSummarySerializer" />
+  <adapter factory=".deserializer.ScheduleFieldDeserializer" />
 
   <unconfigure>
     <adapter factory="plone.app.imagecropping.dx.CroppingUtilsDexterity" />
diff --git a/src/imio/directory/core/contents/contact/deserializer.py b/src/imio/directory/core/contents/contact/deserializer.py
new file mode 100644
index 0000000..3e7a25f
--- /dev/null
+++ b/src/imio/directory/core/contents/contact/deserializer.py
@@ -0,0 +1,29 @@
+from collective.schedulefield.schedule import ISchedule
+from plone.dexterity.interfaces import IDexterityContent
+from plone.restapi.deserializer.dxfields import DefaultFieldDeserializer
+from plone.restapi.interfaces import IFieldDeserializer
+from zope.component import adapter
+from zope.interface import implementer
+from zope.publisher.interfaces.browser import IBrowserRequest
+
+import json
+
+
+@implementer(IFieldDeserializer)
+@adapter(ISchedule, IDexterityContent, IBrowserRequest)
+class ScheduleFieldDeserializer(DefaultFieldDeserializer):
+    """Allow non-ASCII characters (e.g. accented) in schedule comments.
+    The default DictFieldDeserializer recursively validates inner dict values
+    against ASCIILine(), rejecting accented characters. Schedule.validate()
+    already skips the 'comment' key, so we use it directly instead."""
+
+    def __call__(self, value):
+        if not value:
+            return value
+        if isinstance(value, str):
+            try:
+                value = json.loads(value)
+            except json.JSONDecodeError as e:
+                raise ValueError(f"Invalid JSON for schedule field: {e}") from e
+        self.field.validate(value)
+        return value
diff --git a/src/imio/directory/core/tests/test_contact.py b/src/imio/directory/core/tests/test_contact.py
index d60d8e8..4eea1ae 100644
--- a/src/imio/directory/core/tests/test_contact.py
+++ b/src/imio/directory/core/tests/test_contact.py
@@ -286,6 +286,106 @@ def test_overall_response_format(self):
             "items_total property should match actual item count.",
         )
 
+    def _make_schedule(self, comment=""):
+        days = [
+            "monday",
+            "tuesday",
+            "wednesday",
+            "thursday",
+            "friday",
+            "saturday",
+            "sunday",
+        ]
+        return {
+            day: {
+                "morningstart": "09:00" if day not in ("saturday", "sunday") else "",
+                "morningend": "12:00" if day not in ("saturday", "sunday") else "",
+                "afternoonstart": "13:00" if day not in ("saturday", "sunday") else "",
+                "afternoonend": "17:00" if day not in ("saturday", "sunday") else "",
+                "comment": comment if day == "monday" else "",
+            }
+            for day in days
+        }
+
+    def test_schedule_patch_with_non_ascii_comment(self):
+        contact = api.content.create(
+            container=self.entity,
+            type="imio.directory.Contact",
+            title="contact",
+        )
+        transaction.commit()
+        comment = "uniquement sur rendez-vous à partir de 14h (été)"
+        response = self.api_session.patch(
+            contact.absolute_url(),
+            json={"schedule": self._make_schedule(comment)},
+        )
+        self.assertEqual(response.status_code, 204)
+        result = self.api_session.get(contact.absolute_url()).json()
+        self.assertEqual(result["schedule"]["monday"]["comment"], comment)
+
+    def test_schedule_patch_with_ascii_comment(self):
+        contact = api.content.create(
+            container=self.entity,
+            type="imio.directory.Contact",
+            title="contact",
+        )
+        transaction.commit()
+        comment = "by appointment only"
+        response = self.api_session.patch(
+            contact.absolute_url(),
+            json={"schedule": self._make_schedule(comment)},
+        )
+        self.assertEqual(response.status_code, 204)
+        result = self.api_session.get(contact.absolute_url()).json()
+        self.assertEqual(result["schedule"]["monday"]["comment"], comment)
+
+    def test_schedule_patch_with_empty_value(self):
+        contact = api.content.create(
+            container=self.entity,
+            type="imio.directory.Contact",
+            title="contact",
+        )
+        transaction.commit()
+        response = self.api_session.patch(
+            contact.absolute_url(),
+            json={"schedule": {}},
+        )
+        self.assertEqual(response.status_code, 204)
+
+    def test_schedule_patch_as_json_string(self):
+        import json
+
+        contact = api.content.create(
+            container=self.entity,
+            type="imio.directory.Contact",
+            title="contact",
+        )
+        transaction.commit()
+        comment = "réunion hebdomadaire"
+        schedule = self._make_schedule(comment)
+        response = self.api_session.patch(
+            contact.absolute_url(),
+            json={"schedule": json.dumps(schedule)},
+        )
+        self.assertEqual(response.status_code, 204)
+        result = self.api_session.get(contact.absolute_url()).json()
+        self.assertEqual(result["schedule"]["monday"]["comment"], comment)
+
+    def test_schedule_patch_with_non_ascii_time_field(self):
+        contact = api.content.create(
+            container=self.entity,
+            type="imio.directory.Contact",
+            title="contact",
+        )
+        transaction.commit()
+        schedule = self._make_schedule()
+        schedule["monday"]["afternoonend"] = "17:é0"
+        response = self.api_session.patch(
+            contact.absolute_url(),
+            json={"schedule": schedule},
+        )
+        self.assertEqual(response.status_code, 400)
+
     def test_subscriber_to_select_current_entity(self):
         contact = api.content.create(
             container=self.entity,