Why did Abd el-Krim surrender to the French instead of the Spanish?

Abd el-Krim surrendered to the French on May 27, 1926, rather than the Spanish, because the French offered him specific terms for his surrender. In exchange for the immediate release of all French and Spanish prisoners and the unconditional surrender of his forces, the French promised protection to both him and his family.1

Following this agreement, Abd el-Krim and his immediate family were exiled to the French island of Réunion in the Indian Ocean, where they remained for 21 years. This decision to surrender to the French was a significant conclusion to the Rif War, a conflict in which he had successfully organized indigenous resistance against both colonial powers before being overwhelmed by their combined military strength.12