Les Sept-Iles, France
This groups of seven islands off the coast of Brittany holds a large Gannet colony and is the southernmost breeding location of the Atlantic Puffin.
These five (not seven) islands, off the coast of Côte de Granit Rose (pink granite coast), boasts the only colony of Northern Gannets in France, in addition to the southernmost breeding grounds of the Atlantic Puffin and other auks. Boat trips are available from Perros-Guirec, a popular sea-side resort, and Port-Blanc.
A two-hour boat trip (advance booking recommended) will take you out to the islands, with excellent view of the gannet colony. The trip will pass along a few of the islands, and on the way back you will get an excellent view of the pink granite rocks of which the area is famous for.
We had a beautiful day in May on this trip, and the boat was fully booked. The guide will give a lot of information along the way, but in French only. The upper deck is defiantly the place to be, but have few places, so be early in the queue to board the boat.
The Northern Gannet colony is obviously the main attraction, in addition to the Puffins. We saw maybe 5-6 Puffins, so it can hardly be called a prime Puffin location, but they certainly sparked a lot of attention. The Gannets are really thriving here, although nesting material seems to be more thrash than kelp...probably reflects the state of our planet quite accurately.
Both Great Cormorant and European Shag can be seen in good numbers, often side by side.
The Common Guillemot and Razorbill can be seen scattered around the islands. A better place to observe the Guillemot in France is actually Cap Fréhel, 120km to the east. I did see a single Manx Shearwater flying across the water, but no luck making a photo.
In addition to birds, there are also grey seals living around the islands. Frequently found resting on the shore or swimming along.
Les Sept-Iles is a great location for observing Gannets, and the Puffins are a bonus. Well worth a visit when traveling in Brittany.