Did you know you can go surfing on the St. Lawrence River just opposite Port Montreal, in Cite-du-Havre? That revelation is one of scores shared by author Philippe Renault in the just-out “Secret Montreal: An Unusual Guide” (Jonglez Publishing, $21.95). The permanent wave is caused by a ditch dug during Expo 67 construction. While you’re in the area, he advises, check out Habitat 67, a group of avant-garde homes by Somerville-based architect Moshe Safdie. If you’re looking for a different waterfront view, Renault lets readers in on the little-known fact that the famed spire of Notre-Dame-de-Bon-Secours Chapel can be climbed “for the most beautiful view of the Old Port.” Jonglez Publishing also just released the equally revealing “Secret New York,” by T.M. Rives ($19.95).