This construction is a bee hotel in Paris, designed for bees to live and lay eggs. While some bees build hives, there are species of solitary bees that can’t live in beehives and need their own nests. These species don’t have many suitable places for nesting in urban areas, so people build such hotels of stones and wood with drilled holes. Here are the pictures of various bee hotels from around the world.
Gorgeous, not all bees are hive minded. Structures like this are built for mason and bumble bees who do not live communally.
With the decline in honey bees, farmers have turned to mason bees and such in order to pollinate their crops.
At any rate, those are awesome looking structures. I'll have to fiddle around a bit and emulate the nicer ones in the garden.