you got that mixed up: you would apply at the french embassy in the US. and, that's the key point for schengen: you would not apply at the eg german embassy in the US, even though both would get you the same visa. the US embassy can't give you a schengen visa, and you could not even get to the one in france since you are not there yet. and if you visit multiple countries, it's either the one where you spend most of the time, or the one where you enter the schengen area (this may be different from the country you visit first because you could have a flight transfer inside schengen). at least as far as i know.