Spain and chemical weapons in Morocco

Joerg in Berlin sent me this:  "Spain still does not recognize the use of chemical weapons against the Moroccan Rif Republic under the Emir Abdelkrim in the 20s. These weapons were delivered by Germany and France, though Germany was not allowed to produce, host, or export it, because of the WWI peace treaty. Normally this subject is "tabu" in Morocco. In 2001 (?) Morocco cancelled an international conference about the War in the Rif Mountains, probably because they did not want to embarrass Spain." (I remember that I read once that France used chemical weapons in the 20s in Syria, but I do not find it anymore".)