I can verify that Lelystad airport in The Netherlands has Mogas available, the Cessnas I rent there all run on it.
Website:
click here
To check for Mogas availability you could have a look through the Dutch AIP on this page:
http://www.ais-netherlands.nl/ (select 'AIS publications' on the left, agree to the terms and choose the 'Integrated Package', it is in English).
As for France, I cannot answer that part of your question. My suggestion would be to start with the French AIP. If you go to a local (largish) FIO they might have it available, alternatively it may be available online.