The book I’m looking for is about a young boy (early teens) in post World War 2 France. There is a tavern called the Red Dragon and I know it’s referenced in the title of the book. The plot is this young man foiling attempts by Nazi survivors to sabotage various historical events, including the Cuban missile crisis. The young Frenchman makes personal friends with JFK and goes on to save his life several times from ex-Nazis. The boy’s parents were part of the French resistance and the secret society of the red dragon. That’s all I can remember.