Isn't French molt an older name for Polyoma virus? Budgies are frequently carriers, usually asymptomatic though.
The baby you have is sure to be infected as well, but probably just a carrier. For birds other than budgies, it's very dangerous to babies, but usually harmless to adults. It's just something to be aware of. If you ever get another bird in the future, especially if it's a baby, you should get it vaccinated for polyoma first.