How do I find out if the police have a file about me?

Everyone has the right to see their own file.
You can find out if there are any records about you by submitting a written request.
You have to include a copy of your identity card,
and it can take up to 30 days before you receive a reply.

Kantonspolizei Bern
Rechtsdienst
Waisenhausplatz 32
3011 Bern

You can find more information in German and French on the cantonal police website:
Data privacy / your rights