Ulysse Nardin Chronograph Calendar.
My guess is that it could well be from the 50's or 60's, with its yellow gold case, its triple date and its chronograph. A pure marvel of classicism I had the pleasure to see some 3 years ago.
It is such a beauty that I didn't forget it. I would have loved to see it in white metal... Even if gold is not bad looking at all for such a classic watch.