French TV uses DVB-T with MPEG2 coding for Standard Def, and MPEG4 for High Def... so a UK Freeview HD box would be best to use. (SD Freeview won't be able to decode the French HD channels).
Digital terrestrial television - Wikipedia, the free encyclopedia
Some TVs with integrated tuners will be able to, though, if you can choose countries on installation... but not all do! You'd need to check the specs out!
A Freeview box won't assign the French stations in their French 'logical channel number position, but they are usually stored in the 800s (as are UK out of region or duplicates).
If you want a separate box for Franch only use (with a separate aerial directed to France) then a box from France would, perhaps, be better (if your French is good enough for the menus etc.,.).