Trail Connect suggest you plenty of layers, for France, Europe or the entire world.

By using the app, you will have the possibility to overlaid the layers for a best analysis of the field. You will be able for example to overlaid the layer IGN 25:000 with the hills layer. 

With a subscription, you will be able to overlay on a map the Strava heatmap (data available for all sports, for pedestrians, cycling, winter and nautical practices, cycling practices) which will allow you to discover the paths and routes which are the most frequented.