I just made Silver Medallion on Delta on my trip to France last week and I have the return trip coming up on Friday. My return flight is an Delta flight on an Air France plane. I'd like to be able to check both of my bags on the way home (SkyTeam Elite benefit), but I can't tell if AF has me as an Elite yet. Delta.com shows my status, but I can't find it anywhere on AF's website. Does anyone know how I can check or if there is a delay in transferring the information?

It's a DL booking (006 ticket number) with a DL flight number but AF-operated? If so, I'd call DL and ask them to remove and reinsert your SkyMiles number. That should force the right data over to AF.

Alternatively, print out a page from your FFP's account that clearly shows that you have silver status with DL.

I had a same situation on KL last year (FB elite to FB elite plus during a flight).
3 days later when returning it was not yet mentioned in the system they use when doing the check-in although it was mentioned on the FB website.

In Amsterdam I asked the FB helpdesk and one mentioned that a status change would take somewhat around one week to post on the internal systems of KL/AF.

Welcome thirtyfour!
If DL shows you are a FO, go to AF.us and find your reservation using your e-ticket number (starting by 006). Then, try to change your FF number. If you cannot, can you give them a call to do it? Or print a page from DL.com stating you are ST Elite now.
But do not forget it can take time your status change appears in their database.

I wanted to mention that my DH flew out of WAW to the states on AF last year. He has FO Delta, and had to fight with the gate agent to let him check two bags.

I had printed out copies of all the information and the fact of his silver status and he had all that with him. But the agent didn't want to do it. But my DH insisted, showed him the papers, and he finally let him have the two checked bags.

It is a real help to us as we are trying to get college kids' stuff back to them in the states (we live here but are Americans, so most of our kids' stuff is here.). A piece of luggage at a time will do it, but every bag helps!

Except for actually transporting "stuff", however, we do fly just with carry-ons for our travel needs. It's a lot easier.