From: The Divided Nations of Earth
The Algerie was kinda flimsy. They had no tonnage for armour at all.
juts looking a refernce i have says
"armour was extensive and totaled 2657 tons as opposed to 1553 tons with the Duplex, inboard of the main belt was an anti-torpedo bulkhead, extending from the bottom to the armoured deck and enclosing the end barbettes, with space between divided into oil fuel and coal bunkers for additional protection"
Navies of the second world war, The French Navy, Vol 1,2
Here's from Conway's:
Authorized in 1930, this vessel was the last and best French 'treaty' cruiser, and one of the most outstanding examples of the type in any navy. A radical departure from the widely criticized 'tin-clad' heavy cruisers, she was built in response to the Italian Zara Class. Armor weight totaled 2657t (compared with 1553t in the preceding Dupleix) and it was better distributed; emphasis was placed on protection against aerial bombs and underwater attach, and extensive torpedo bulkhead being separated from the main belt by old and coal bunkers.
Of course saying that it was the "best 'treaty' cruiser" is maybe not saying a whole lot.