An enigma lies at the heart of this article. In December 2006, the mayor of Saint-Étienne, Michel Thiollière, was elected as the fifth best mayor in the world by the internet site City Mayors. Yet no publicity was made locally around this award. Taking this anecdote as a starting point, this article deals with the motivations that can lead a city mayor to become involved in urban international relationships' policy (city twinning, participation in cities networks, study trips, etc.). (...)