I'm glad I discovered this thread (via the 50+ forum) which I check out from time to time. I was wondeing what type of bike it was that my wife was riding at the time.
Hey, I rode it a few times, too -- it's a fun bike (although to say a little on the heavy side is understatement.)
The mixte, A Peugeot is the second from the left, back when it was seeing some consistent action.
Right now it needs some TLC and a the front derailleur needs to be replaced.