Didn't see one that fitted my needs so I build my own.
Edit the fitbit.py file with your consumer key and secret.
import fitbit
z = fitbit.FitBit()
Make a request token:
auth_url, auth_token = z.GetRequestToken()
Visit the auth_url and copy the PIN. Use the PIN to get an access token:
access_token = z.GetAccessToken(PIN, auth_token)
Store the access_token for later usage. You can now call the API with it:
response = z.ApiCall(access_token, apiCall='/1/user/-/activities/log/steps/date/today/7d.json')
All responses for the functions are received in JSON but are also available in XML.