Boulogne-sur-Mer

The walkway atop the 13th-century medieval ramparts rings the old town for nearly 1.4 km, entirely in the open air. Leashed dogs are welcome for a panoramic stroll above the rooftops and harbour; the cobbled lanes of the Ville Haute inside are also walked on lead.

The 19th-century neoclassical basilica, topped by a dome visible across the town, dominates the Ville Haute and holds a vast crypt. As in most places of worship, dogs are not allowed inside or in the crypt, but the forecourt and surrounding streets can be visited on lead.

The national sea centre, one of Europe's largest aquariums, features huge tanks and a tunnel beneath a tropical lagoon. As in all aquariums, only assistance dogs are admitted inside; the seafront and the beach right in front stay open for leashed walks.

The 13th-century comital castle, one of the earliest keepless castles in France, now houses a museum with rich collections of antiquities and art. Dogs are not allowed in the museum rooms, but the moat and ramparts around it make a pleasant leashed circuit.

A few kilometres north, these two headlands, a listed Grand Site de France, raise cliffs facing England and are crossed by GR 120 trails. Leashed dogs are welcome for spectacular coastal walks; keep them well back from the cliff edges and away from the sheep grazing the grasslands.

The wide sandy beach below the sea wall, extended by the promenade, offers long walks facing the Channel. As on most French beaches, dogs are restricted in high season (summer bans are common) but regain much freedom off-season; check the current municipal by-law.