Antoine de Massy, Prince Albert II's Cousin, Dies Aged 29 in Monaco

Antoine de Massy, a first cousin once removed of Prince Albert II of Monaco, has died aged 29, the Prince's Palace announced on Monday, October 26, 2026. His body was found early on Sunday evening, October 25, in a park below Boulevard du Larvotto in Monaco.

Prosecutor General Stephane Thibault confirmed the discovery. De Massy's family had raised the alarm, and Monaco police searched for him before his body was found in the park below the boulevard.

Cause of death not established

An investigation has been opened to establish the cause of death, which has not been established. The prosecutor's account, reported by Monaco Life, leaves every possibility open at this stage.

A man who approached de Massy on Boulevard du Larvotto was arrested on Monday morning. His custody was extended by 24 hours on Monday evening. Thibault stressed that the man's role remained unclear and that all possibilities, including an accident, were being considered. He is reported here only as a man who approached de Massy and was questioned. Prosecutors have not described him as a suspect in a killing, and no cause of death has been announced.

A family closely linked to tennis

Antoine Alexandre Denis de Massy was born on January 15, 1997. He was the son of Christian de Massy and Cecile Gelabale, and the grandson of Princess Antoinette, the elder sister of Prince Rainier III.

He began playing tennis at the age of three and later moved to Florida to train. He studied at Florida International University between 2016 and 2019. In December 2021 he co-founded Instant App, a Monaco company working on software and digital platforms.

Tennis ran through the wider family as well. His aunt Elizabeth-Ann de Massy led the Monte-Carlo Country Club and the Monegasque Tennis Federation until her death in 2020. That role is now held by Melanie-Antoinette de Massy, who also heads the Rolex Monte-Carlo Masters.

The Prince's Palace communique, as reported by Monaco Life, said: "Passionate about tennis, he was part of a family history closely linked to the sport in the Principality."

A low public profile

De Massy held no official role in the Princely Family and kept a low public profile, according to Monaco Life. His death was announced by the Palace in its communique on Monday, a day after his body was found.

The Palace said: "Their Highnesses share in the grief of his family and loved ones and extend their sincere condolences at this painful time."

The investigation into how he died continues. Until prosecutors establish a cause of death, the facts that are confirmed are limited to the announcement, the place and time his body was found, and the questioning of the man who approached him on the boulevard.