This house rule adds a Vichy French and Free French rule that is easy to comprehend and implement in any game.
It allows a semi realistic Vichy France to be in game that varies in strength as well as beef up the United Kingdom navy which helps balance it and you really get a feel of the Royal Navy being a formidable force. It is a bit of a downer when Germany turn 1 takes out almost all the United Kingdom ships.
It gives Germany some extra navy units to include a transport which helps get an Afrika Korps in the game that we rarely see in the out of box game. However, these ships are not accessible until turn 2. So, the United Kingdom has a chance to take them out.
This house rule has some play testing, but far from perfected. If you have feedback, questions or concerns let me hear them.