Flask-Admin is advanced, extensible and simple to use administrative interface building extension for Flask framework.
You're not limited by the default functionality - instead of providing simple scaffolding for the ORM models, Flask-Admin provides tools that can be used to construct administrative interfaces of any complexity, using a consistent look and feel.
Flask-Admin is extensively documented, you can find documentation here.
3rd Party Stuff
If you want to localize administrative interface, install Flask-BabelEx <https://pypi.python.org/pypi/Flask-BabelEx> package.
Some ideas were taken from the Flask-Admin by Andy Wilson.
The library comes with a few examples, you can find them in the examples <https://github.com/mrjoes/flask-admin/tree/master/examples directory.