The second photo is "Entrée du Méchouar".
Both photos are of the 1860's. The photographers Neuerdien (brothers) held a very well known studio in France. Both brothers work in different issues. One was focused in the portrait and administration (Etienne Neuerdien) and the other one (Louis Antonin Neuerdien) travel a lot and took pictures from different places to be sold in Europe.
This means that both of these pictures probably belong to Louis-Antonin Neuerdien because these are pictures of Algeria.
Their photos were sold under the name of X photo. The pictures were signed with N. D. One of their important works was to took pictures of monuments, castles and churches of France. His labour was recognized by the Goverment of France. They worked until 1915.
The archives of the Neuerdein brothers (Frères Neuerdein) are included in the Michael project (Multilingual Inventory of Cultural Heritage in Europe).