World 800 metres champion Pierre-Ambroise Bosse has sustained facial fractures after being subjected to an alleged "violent assault" by three people.
Bosse claimed he was attacked last Saturday and would be bringing an end to his season as a result of the injuries suffered.
The Frenchman, who took gold at the IAAF World Championships this month, said an investigation into the incident is under way.
"Last Saturday I was the victim of a violent attack," Bosse wrote on his official Facebook page.
"Three people brutally assaulted me. The consequences: multiple facial fractures, many days of inactivity, unquantifiable moral damage.
"An investigation is under way. For all these reasons, my season stops from this day.
"I've always loved people. Today I love three less."