Time connection in CDG

You probably mean immigration not "customs" - and yes, you go through immigration in Paris, because that's where you enter the Schengen zone. The 10 second "customs walk" (for most people) would be done in Barcelona with your bags as you exit through baggage claim; unless you have something to declare it's nothing.

The question is, is there another flight to Barcelona from CDG on the same airline soon after the one you are hoping to get on? If so, I wouldn't worry so much, because you'd very likely get put on it, unless it's completely full because you are traveling at a very busy time. Delays can always happen, so you could well miss your connection to Barcelona if you arrive late in CDG, but 90 minutes would probably be just adequate if you are on time.

If it’s all one one ticketed itinerary—maybe if your first plane is on time, you are seated not too far from an exit, you don’t need to be bused in from a landing area further out and you can be at the other gate area 20 minutes before boarding. Maybe, depending on how many jumbo jets have landed at the same time putting hundreds and hundreds in line for passport control. So, the bottom line is, don’t know. Too many variables.

If separate tickets, probably not. You’d have to collect your luggage and go check in somewhere else in addition to the above. When you miss your flight in this scenario, you’d be called a no-show, which would cancel the rest of the itinerary on the separate ticket.

Thank you all, you have made up my mind. Especially you Bets, we just had that scenario a couple of weeks ago where they landed us out on the tarmac and we had to be bussed in to the terminal. I think we'll stick with a minimum 2 hour layover