-Defending Paris in unlimied gas scenario-
The highest rush chance to take Paris is round6. Typically Germany will buy 20 stomtruppen+10 field gun. And Austria will buy 20 Gas.
As France you should send all N.African cavalries to Cairo. Don't buy any naval vessel, don't farm anywhere. Need to buy cavalries for Brittany and fighters for Marseille in r4 (if possible) for quickly moving them Paris.
As Italy buy 6 cavalry in Rome, 1 figher+1 field+1inf in Piedmont. Send Cavalries to Rhone in r4 and buy 3 fighter in Piedmont than send all of them to Paris.
As Britain buy 5 fighter in London, 1 destroyer in Canda and a few land units for Cario only in r1. Build England fac in r2. If Germany hits Belgium in r1. Try to stack Picardy if Germany ignore Belgium in r1. Keep Belgium as much as possible. Buy 8 fighter in r4 in Britain.
As Russia minimum investment against Commies, Ottomans and recapturing Warsaw, taking Scandinavia and Gas Rush to Galicia in r4-r6.
As USA not buying S.Fransisco fac in r1 and sending troops to Paris.