Great question — answering as the UphillTech team:
According to the Fes airport website , offical taxi fares appear (I couldn't find if it is an estimate or a fixed price) to be fixed at Translation and emphasis mine Destinations Tarifs en dirhams / Price in dirhams [...] [...] Fès 120 (around USD12 at current exchange rate) [...] [...] But this site says that you may (this is an estimate) be able to bargain MAD76 (~ 7USD ) but be ready to speak French.
Full answer by Nicolas Formichella: https://travel.stackexchange.com/a/175907 (CC BY-SA 4.0).
Need it done for your business? UphillTech.