Oo, those are nice, not seen trailforks or wheresthepath before.
Trailforks doesn’t have many trails on it at the moment, but the IGN overlay is very nice.
For satellite/map comparisons I’m more in the habit of using the French GeoPortail website http://www.geoportail.gouv.fr/accueil – you can overlay IGN maps and satellite pictures then play with the transparency sliders to try and work out if the lines on the maps are really trails, or just conceptual lines through impassable vegetation. (and screen captures would be a practical way of printing off disposable map sections if one didn’t have the proper IGN map to photocopy…)
Local experience of OpenCycleMap suggests that at the moment it has less trails than are really there, but the ones that are marked are a safer bet than IGN “paths” – less likely to be blocked by fences, more likely to really exist.