Layover at CDG, do I have to claim luggage, go thru customs and recheck for Barcelona?

I think not if you have checked Barcelona as your final destination at the initial check in...the luggage should go all the way to Barcelona direct.

Your checked luggage will go to Barcelona and you'll take it through customs there.

Assuming that you'll not stay in the same sub-terminal in Paris and do something with the layover besides sit on your duff, you'll pass through immigration and the customs walk-through as you exit the terminal arrivals hall with what you're toting.

Since both legs are on the same carrier, they will check you bags all the way through to Barcelona. If you were switching to a carrier without an interline agreement, such a EasyJet or RyanAir, then you would have to claim and re-check the bags. You will go through Passport Control at CDG, and if you're leaving the secure part of the airport, you'll go through Customs, but just walk through the gate for "nothing to declare."