Ah, I would have confirmed that for you in advance had I known. I do have plenty of experience flying combinations of DL/AF/KL/AZ on DL tickets and codeshares. FWIW, that particular TATL JV (too many acronyms - transatlantic joint venture) is really well-integrated from a customer perspective. They all seem to handle one another's customers if you need help, and you don't get much pushback on technicalities like ticket stock and marketing carrier.

Not to go to full tangent mode, but a solid example: Earlier this year I had a ticket FLR-CDG-BOS, on Alaska Air stock, AF operated (and AF flight numbers). Fog out of FLR canceled the flight, with an Italian twist - they moved it to BLQ. We got to BLQ, but not in time. We ended up getting help from a KL agent, who put us on BLQ-CDG (AF), CDG-AMS (KL), AMS-BOS (DL). They did a really nice job. The only thing they wouldn't do was endorse the ticket to UA, who could have gotten us home same day - they initially wanted to, but said they could not because Alaska issued the ticket and it was an award, which in hindsight I thought was fair enough.

IMHO, Skyteam is the way to go from the US to Europe (on DL/AF/KL/AZ), but that's just my opinion. My experience isn't all-encompassing, but I've flown all 3 alliances enough to say that this group does the best when things go wrong. *A and OW seem to at least try to find a reason where it's the customer's fault, but I've never gotten that treatment from ST.