Facebook Connect for Flask
The Flask-OAuth extension supports Facebook authentication:
facebook = oauth.remote_app('facebook', base_url='https://graph.facebook.com/', request_token_url=None, access_token_url='/oauth/access_token', authorize_url='https://www.facebook.com/dialog/oauth', consumer_key=FACEBOOK_APP_ID, consumer_secret=FACEBOOK_APP_SECRET, request_token_params={'scope': 'email'})Here's a full Facebook example: https://github.com/mitsuhiko/flask-oauth/blob/master/example/facebook.py
You might also want to checkout Flask-Social as well (which is an extension on top of Flask-Security). I'm in the middle of setting it up myself, but so far no issues. Flask-Security, if you're not familiar, combines Flask-Login, Flask-Principal, and a few other extensions for a quick security layer, and Flask-Social adds the OAuth features.