I download my French TV listings from a great website called Kazer.
I download these using wget then insert the listings manually using mythfilldatabase run using cron ever few days.
With Mythtv 0.25 this has changed and there are new options for Mythfilldatabase:
$ mythfilldatabase --file --sourceid--xmlfile belgium.xml
Previously it was:
$ mythfilldatabase --filebelgium.xml
I strongly recommend Kazer if you need French listings. It’s free although every other year I donate 20 Euros or so.