"my room in the Grand Hôtel de la Plage"
Grand Hôtel Cabourg
In Cabourg, Proust's model for Balbec, there is a Grand Hôtel Cabourg on the seafront. Proust stayed here in the summers of 1907 and 1914. It is the likely real-life equivalent of the Grand Hôtel de la Plage, and has acknowledged this by callings its restaurant Le Balbec. See also the bookmark to p. 155 "you're going to Balbec