Thanks, Stephen. It is the Chateau (castle) de Saint Germain en Laye, a royal castle in the vicinity of Paris. It is, incidentally, where James II of England and James VII of Scotland died in exile after the Jacobite episode.
It was built and then modified in many stages, and, lastly, at the hands of restorer Viollet-le-Duc, who believed not only in restoring old buildings, but also in "improving" them... hence the very mixed style.