Del's always at hand with a bucket of cold water! There are other things on TV apart from Le Mans. You can always walk to the track to watch the race, armed with a set tuned to Radio Le Mans.
Yes, the box from Lidl will work in France. The race will be broadcast on Canal+ and CanalSat in France, both of which require subcription. You will be able to get the free stuff from all over Europe including BBB 1 and 2 and ITV on it.