Originally Posted by San Gottardo

Sure, with pleasure.

In in fact in true Air France style it was a bit messy:

• Asked at the welcome desk of the Skypriority check-in are where to check-in, staff there told me we should check-in right there, so we stood in line.
• After 15 Minutes, at the counter, a very authoritative AF person told us in a way that suggested that it was our fault that there is no way we could check in here. We would have to go “down”, without saying where exactly, as that would be where they’d *always* check in UMs
• Downstairs we asked our way through, misdirected a few times by AF staff (to upstairs, to the counter where UMs are picked up, etc) to finally find the right check-in zone. It was on arrivals level, by door 16
• Once there, the staff there told us that the counter was closed and “never” opened before (I think 9am) and that we’d have to go upstairs. This despite five or six AF staff there, computers booted and all ready to go, and the official opening time in only ten minutes
• One of the staff then showed some common sense and “opened” the counter.
• There was some confusion about the paper work, I basically had to explain them which papers they needed (pickup form, permit for kids to leave the country, parent’s passport photocopy), which I had all brought along. They insisted that they wouldn’t need the parent passport photocopy and binned it
• A very nice AF agent took the kids and off they went
• 10 Minutes later I received a call from that AF agent, asking me to return so that they can take a photocopy of my passport

The takeaway for you is:

• The counter is on the arrivals level by door 16. At least at certain times
• Know what you are doing and what is needed, because they may not know
• Take plenty of extra time, because you may need to spend it on wrong information and otherwise clueless staff

One more word of caution: this UM check-in counter *seems* to be open only during French vacation periods, at least the people there said they *thought* that was the case.

Sorry I cannot share any more robust information, but this is as reliable as it gets with AF. Still I hope it's somewhat useful.

PS: in 2F, the check-in counter for UMs is all the way to the left when entering the terminal.