A recent article here on Heritage Key by Bija Knowles looked at Roman sites across the South East of France. There are many sites across the area which remain today as relics to the Roman past, the empire having controlled the area as early as 125BC.
The map shows the triangle area between the towns of Nimes, Arles and Orange where many of the heritage sites reside, but also includes Lyon which also has many notable Roman settlement relics.
Using this interactive map, you can see the exact locations of these sites, and easily plan your (real or fantasy) trip through Roman France.