Saint-Gingolph is a small town situated on the south bank of Lake Geneva (Lac Léman).
The town played an important role during the World War II when Haute Savoie was occupied first by the Italian and then by the Nazi German Armed Forces.
The fact of large-scale intermarriage and business and family connections across the frontier made it possible for the Resistance to smuggle goods, arms and refugees (including many French Jews) across the border, often using a secret tunnel (no longer in existence; it was actually a drainage pipe) located near the lake.
These stories are documented in a book privately published in 1994 by the late André Zénoni, "Saint-Gingolph et sa région frontière dans la Résistance 1940-1945".
(Intermarriage across the frontier is less frequent in the modern age because there are separate primary schools ("L'École André Zénoni" on the French side) and French lycéens are bussed to Evian, while Swiss students take the train to Monthey.