Monaco mourns Antoine de Massy, 29, as authorities investigate his death

File photograph: members of Monaco’s princely family with tennis players at the 2026 Monte-Carlo Masters; Antoine de Massy is not pictured. — Jean Catuffe / Getty Images

Summary

Antoine de Massy, a member of Monaco’s extended princely family, has died aged 29.
The Prince’s Palace issued a statement of condolence Monday.
Monaco’s prosecutor said an accident has not been excluded; a detained person’s role remains under investigation.

Palace offers condolences

Antoine de Massy, a 29-year-old member of Monaco’s extended princely family, has died after his body was found Sunday, October 25, in the principality. Prince Albert II and Princess Charlene expressed their sadness Monday. Authorities are investigating the circumstances, and the cause of death has not been publicly established.^{[1] [3]}

The Prince’s Palace identified de Massy as a grandson of Princess Antoinette, the elder sister of Prince Rainier III. Its statement offered condolences to his family and loved ones and highlighted his enthusiasm for tennis, describing him as part of a family with longstanding connections to the sport in Monaco.^[2]

Circumstances remain unresolved

Monaco prosecutor general Stéphane Thibault told AFP that an investigation initially opened to determine the cause of death had been expanded so investigators could detain a man seen with de Massy on video. The prosecutor emphasized that the person’s role and the legal characterization of any possible events remained to be determined.^[1]

Thibault expressly said that an accident had not been excluded. His description of the detained person as potentially a suspect or a witness leaves the circumstances unresolved. The available official comments reported by AFP do not establish that de Massy was killed by another person or that the detained man committed an offense.^[1]

His place in the family

De Massy was the son of Christian de Massy, a first cousin of Prince Albert II. That made Antoine the sovereign’s first cousin once removed. His grandmother, Princess Antoinette, was Prince Rainier III’s elder sister and Prince Albert’s aunt, placing him within the wider family rather than the sovereign’s immediate household.^[3]

The family’s tennis connections extend across generations. His grandfather, Alexandre-Athenase Noghès, was a Monegasque player. His aunt Elizabeth-Ann de Massy led the Monte-Carlo Country Club and the Monegasque Tennis Federation until her death in 2020. Her daughter, Mélanie-Antoinette de Massy, subsequently took leadership roles in those institutions and the Rolex Monte-Carlo Masters.^{[3] [5]}

A longstanding interest in tennis

A 2012 L’Uomo Vogue profile provides a direct account of de Massy’s early sporting ambitions. He recalled being introduced to tennis by his father at three and later moving from Monaco to Florida for intensive training alongside his education. The profile presented a young player choosing to devote substantial time to the game.^[4]

In that interview, de Massy discussed admiring Novak Djokovic’s technique and personality and hoping to represent Monaco at the Olympic Games. He also expressed an ambition to reach the top of the world rankings. Those were aspirations described in the 2012 profile, not a statement of subsequent competitive results. Monday’s palace tribute returned to that enduring interest in tennis.^{[2] [4]}

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