Ditto...

I have actually NEVER seen anybody at Customs when arriving at CDG so early in the morning - which is virtually every time you fly transatlantic USA --> France.
They probably check in at 9:00 and start with a coffee break like most people here in France

Immigration should be longer but still okay, few flights arrive around this time. Mid-day is hell.
If I remember correctly, there should be the first customs checkpoint you run into right out of your plane (this one the most crowded), but keep walking further a little bit, like you're doing a circle around the terminal, and there should be another one, usually much less crowded.
@Jouy31 - do you confirm ??

Cheers,
J-