What occupied Richelieu's aft secondary-turret block?

What was inside the structure between Richelieu's aft six-inch turrets?

It housed the ship's aircraft hangar and storage; a lift to below-deck stowage would have been a possible alternative arrangement.

The block between Richelieu's aft six-inch turrets housed the aircraft hangar and supporting storage. That choice explains why the mounts sit around a substantial central structure. A lift and below-deck aircraft stowage could provide an alternative, although this remains a hypothetical modification. The arrangement connects Richelieu's less satisfactory secondary arcs with the competing demand for embarked aviation space.