The Lalla-Marnia Treaty was signed on March 18th 1845 between the plenipotentiaries of the Emperor of France and the Emperor of Morocco. As referenced in article 1 of the Treaty, the two plenipotentiaries agreed that the boundaries that existed between Morocco and Turkey remain the same between Algeria and Morocco. The second article delimits the agreed boundary, it is permitted to say that everything towards east belongs to Algeria and everything towards the west to Morocco. The third article describes accurately the delimitation line. It is also used, for definition, the names of the tribes that had settled there. So the tribes mentioned are Beni – Mengouche Tahta and Aâttïa. These are subjects of Morocco that came to inhabit the territory of Algeria for an annual rent. But the plenipotentiaries commissioners of the Emperor of France agreed in not demanding any rent. The fourth article concerns specifically Sahara. It mentions that there isn’t a territorial boundary established between the two countries, since the land isn’t tilled and serves only as a passage for the Arabs and for the two Empires that come to station there in order to find pasture and water which are necessary to them. It then enumerates the tribes which depend on Morocco and those on Algeria. The fifth article is relevant to the villages of the desert of the two Empires. The most surprising article is without doubt the sixth since it defines that beyond the villages of the desert, there is no water and the land is uninhabited so the delimitation would be superfluous. As for the seventh article, it predicts that no violent return be applied to an individual that has abandoned his country. Therefore the trace of the line is defined at 165 kilometers. Even after the colonization of Morocco in 1912, the delimitation has not been made clear and we observe differences between the Varnier line (1912) and the Trinquet line (1938). In reality, we had to wait for the discovery of the fields of oil, of iron and of manganese in order for France to precisely delimit this region. It is only in 1952 that France incorporates in the French departments of Algeria the regions of Tindouf, Colomb Bechar. So Morocco, since its independence, vindicates these territories on the base of historic Morocco. France proposes the principal of restitution in parallel with the existence of a common organization of the Saharan regions. The King of Morocco prefers an agreement in 1961 with the provisionary Governor of the Republic of Algeria, only that the latter was evicted during the independence of Algeria. This will finally lead to the sand war (1963-1964).