diff --git a/cfp/models.py b/cfp/models.py
index c0d57c6..a55c2d1 100644
--- a/cfp/models.py
+++ b/cfp/models.py
@@ -344,7 +344,7 @@ class Talk(PonyConfModel):
     duration = models.PositiveIntegerField(default=0, verbose_name=_('Duration (min)'))
     room = models.ForeignKey(Room, blank=True, null=True, default=None)
     plenary = models.BooleanField(default=False)
-    materials = models.FileField(null=True, upload_to=talks_materials_destination, verbose_name=_('Materials'),
+    materials = models.FileField(null=True, blank=True, upload_to=talks_materials_destination, verbose_name=_('Materials'),
                                      help_text=_('You can use this field to share some materials related to your intervention.'))
     video = models.URLField(max_length=1000, blank=True, default='', verbose_name='Video URL')
     token = models.UUIDField(default=uuid.uuid4, editable=False, unique=True)