It is a naval battle with a difference, on the shores of the Mediterranean in southern France.
The ammunition is flowers - bunches of mimosa and carnations to be precise.
Thousands gathered in Villefranche-sur-Mer near Nice on Monday for the annual event dating back more than a century.
While locals in boats do the throwing, spectators do the catching. They rarely retaliate but love the floral fiesta.
"Oh it's great, really good! It's an amazing party. It's wonderful," said one visitor, Lucette Senegas from Castres.
Music is part of the mix and while hayfever sufferers may find the flowers a challenge, this colourful carnival is not to be sneezed at!