I ran a few sessions of Athanor, a French sci-fi RPG in the 90s. This game didn't have a real success there : a bit complicated, a bit too ambitious too. But the concepts were neat : our planet has been overwhelmed by man-made viruses and every life form suffer permanent mutation, not every generation mind you, in real time. One can take medicines to prevent that but generally animals, plants and humans have specific traits depending on their local ecosystem. Human populations become very focused on their local ground and quite xenophobic, especially big cities people who live in an hermetic environment saturated with stabilizers. Mutations stimulated psych powers too and the game had many quotes from Philip K Dick Ubik (which I love btw).
I remember was a very nice sourcebook for Venezzia, sci-fi meets medieval culture and carnaval. One of those games I read and reread even if I'll never play them anymore...
Au gibet noir, manchot aimable, dansent, dansent les paladins
Les maigres paladins du diable les squelettes de Saladins.