You can also try
IGN.FR.
It's a commercial site, they sell maps and photos but the search engine is very good, much better than the viamichelin one. Once you have find the complete name or correct spelling at IGN then the Viamichelin search engine will work OK.
Additionally, at IGN.FR, you have the latitude/longitude :
-Type the name of the location in "ma commune" at the bottom right of the homepage, it will give you a list of towns
-Click on the one you are interested (tip: "departements" 02,59,60,62,80 are ok for british front, 51,52,54,55,60,88,90 for french front)
-Choose "les coordonnées de xxxx"
Drawbacks are : it works only for french locations, it knows only "administative" towns or villages, no farm, forest or hamlet.
Hope this helps
gilles