World 800m champion Pierre-Ambroise Bosse sustained "multiple facial fractures" after a vicious late-night attack in the southwest Gironde region of France last weekend, reports Sport24.
Bosse, 25, said on his Facebook page on Wednesday that he was the "victim of a violent attack" while on holiday and had been "brutally assaulted by three individuals".
He said he had suffered "unspeakable psychological damage" as a result of the incident and had been forced to put an early end to his season.
"Me who has always loved people, I love three less of them today," Bosse wrote.
A police investigation is continuing after a complaint was filed, with authorities still on the hunt for the assailants.