diff --git a/app/models/absences.py b/app/models/absences.py
index e6e243b7c0..658a390de4 100644
--- a/app/models/absences.py
+++ b/app/models/absences.py
@@ -49,7 +49,7 @@ class AbsenceNotification(db.Model):
     nbabsjust = db.Column(db.Integer)
     formsemestre_id = db.Column(
         db.Integer,
-        db.ForeignKey("notes_formsemestre.id"),
+        db.ForeignKey("notes_formsemestre.id", ondelete="CASCADE"),
     )
 
 
diff --git a/migrations/versions/1efe07413835_added_cascade_on_absences_notifications.py b/migrations/versions/1efe07413835_added_cascade_on_absences_notifications.py
new file mode 100644
index 0000000000..c568000c10
--- /dev/null
+++ b/migrations/versions/1efe07413835_added_cascade_on_absences_notifications.py
@@ -0,0 +1,30 @@
+"""added cascade on absences_notifications
+
+Revision ID: 1efe07413835
+Revises: 75cf18659984
+Create Date: 2021-11-09 11:49:31.739803
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = '1efe07413835'
+down_revision = '75cf18659984'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_constraint('absences_notifications_formsemestre_id_fkey', 'absences_notifications', type_='foreignkey')
+    op.create_foreign_key(None, 'absences_notifications', 'notes_formsemestre', ['formsemestre_id'], ['id'], ondelete='CASCADE')
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_constraint(None, 'absences_notifications', type_='foreignkey')
+    op.create_foreign_key('absences_notifications_formsemestre_id_fkey', 'absences_notifications', 'notes_formsemestre', ['formsemestre_id'], ['id'])
+    # ### end Alembic commands ###