Is this the high speed French part of the rail system? Will it will send you to the regular French booking site if their is no train on TGV?
tgv-europe.com is part of SNCF, the French Rail system. You can find timetables and fares on it for all types of trains in France, not just TGVs. However, if you leave France as the default country for retrieving your tickets, you will be re-directed to www.voyages-sncf.com (in French). If you choose Great Britain for retrieving your tickets, you will be able to book in English at regular SNCF prices. If you choose the USA as your country for ticket retrieval, you will be redirected to raileurope.com because officially SNCF doesn't mail tickets to North America.