Former French restaurant at Rosedale circa 1980s
I worked at Dayton's Rosedale back in the 80's. I loved that French onion soup too!
I believe it was called Le Petit Bistro. Found this old link, http://www.tripadvisor.com/Restaurant..., which means they must've existed into the internet age.
From my search results, it appears they were a nationwide mall chain.