I was going to stretch the theme by using the name of the yacht, l'Hirondelle or Swallow, but then I noticed there is a seaplane in the foreground. The postcard is one from an unused booklet of Monaco cards.
The yacht, owned by Prince Albert I, was built in 1911 and sold in 1923 which dates the images relatively precisely. There was a "Grand Prix d'Hydroaéroplanes de Monaco" held in 1912, from 24-31 March, almost exactly 100 years ago. It would be nice to think the image dates from then. I don't know if a single seaplane makes a Grand Prix meeting any more than a single Swallow makes a summer, but maybe it lingered on for a week or two.
A post for Sepia Saturday. A click on the button will take you to the blog.