This is a statue of Saint Bertin. Our stony friend stands outside the abbey that bears his name and of which he was the second abbot, some time in the 7th century. For a millennium, the Abbey of St Bertin was active until along came the French Revolution (in France I suspect they may just call it The Revolution) to shut the place down. Still, the building survived until the Second World War when after the town of Saint-Omer was subject to intense bombardment and the old stones gave way.
What remains is a Turner-watercolour-esque shell in a rather nice garden – with our saint as guard. I’m not entirely sure the man who “re-evangelised” the Morini (a non-Celtic tribe occupying land in, but distinct from, the rest of Gaul) would be too pleased with how that’s turned out.