no there is no stand by policy with Air France if you do not have a fully flexible ticket

The only reason AF could move you to an earlier flight is if your initial flight is very heavily overbook and they need to free up some space but it is very unlikly to happen as yield management are pretty accurate now.

in any case you can check with AF what would be the cost to change your MAD-CDG leg. might end up being reasonable.

skiping a leg would most likely cancel all the rest of your ticket