Cheap flights to Le Mans or Chartres?

I'm going to a family reunion in France in September and wondering how to get there.

Flights to Amsterdam and Frankfurt are usually a lot cheaper than flights to Paris.

And intercity flights are often very cheap in Europe I have heard. In fact, Lufthansa charges the same fare from Vancouver to Frankfurt as they do for Vancouver to Frankfurt and a connector flight to Berlin.

So seeing as I want to go to Nogent le Retrou halfway between Chartres and Le Mans on September 7, would I be able to find a flight from Frankfurt fo rexample to Le mans or Chartres fo rexample, or would I hve to go through paris?

I figure if all I can get for cheap is to Paris, I might was well just catch the train from there to Nogent.