Customer service between the two for booking purposes is essentially identical. In fact, you can contact either airline for seat requests or ticket changes. Air France comes out slightly ahead -- at least, for now -- since 1) the CDG hub operation is much less chaotic than Amsterdam Schiphol (meaning the AF customer service contact points are often less overwhelmed), and 2) AF issues fairly convenient PDF e-ticket receipts (hugely helpful to carry with you or to file for reimbursements, etc.).