Longchamps was a chain of restaurants that was highly popular with Ladies Who Lunch in the post-WW II years in New York. There were a number around town, mainly situated around Madison and Fifth. When cheating Fred McMurray's secretary Edie Adams rats him out to his wife in Billy Wilder's "The Apartment," the two women meet at Longchamps. The places were elegant, smart and very Deco. They boasted plenty of mirrors and murals.
They're all gone now, but this sign high about Madison and 49th intrigued me. Sure enough, the address—423 Madison—was once a Longchamps location. It's now a Pax chicken joint.
I found this about designer Winold Reiss, who created many of the stylish Longchamps locations:
The exterior of Reiss's 1941 design proposal for a new bar and roof garden at the 49th Street and Madison Avenue Longchamps displays the chain's trademark vermillion coloring and lettering, including the falling "S," while the undulating lines that enliven its canopy and bronze wall panels recall the early borders of the M.A.C. The entire effect is not dissimilar to that of the Barricini candy box already illustrated: the name or sign identifying the product or establishment has been completely integrated into its design; the façade has become a sign rather than simply providing a place for one.
In 1969, the unctuous, tacky Riese Company—despoiler of classy New York restaurants chains such as Child's and Schrafft's—gobbled up Longchamp's nine locations. But why complain? They gave us Charley O's and Tequilaville in exchange.