Mission Équitation Series

French series of horse games including four single player games, some of which were also released in Germany (and maybe elsewhere?), and a MMO. They were all developped by Lumai Prod and published by Mindscape. Mindscape closed in 2011 but another publisher bought the MMO Mission Equitation Online and kept it alive until 2014. The games were bought after Mindscape bankruptcy and re-sold under the "Real Stories" franchise. In all of these games you play a Manon, a girl that's very talented at communicating with horses, who goes all around the world to try to help horses everywhere.

Moby games entry for the series