Monaco royals

Prince Albert of Monaco mourns cousin Antoine de Massy, found dead at 29 as police investigate


de Massy was the grandson of Princess Antoinette


Prince Albert II of Monaco (L) and Princess Charlene of Monaco (R) arrive to attend a meeting called "At the Roots of Europe: For Peace and Unity" in 2026© AFP via Getty Images
Maria LoretoSenior Writer
OCTOBER 26, 2026 1:17 PM EDT

Monaco is in mourning. Antoine de Massy, a 29-year-old member of the principality’s princely family and a cousin of Prince Albert II, was found dead in a garden in Monaco on the night of Sunday, October 25. Authorities have opened an investigation, and one person was taken into police custody the following morning.

Prince Albert II welcomed ambassadors from the Dominican Republic and Ecuador to Monaco’s palace on October 15, bringing a Latin American presence to a day of diplomatic audiences in the principality.© Pascal Le Segretain
Prince Albert II is mourning the death of his cousin

The alarm was first raised over a missed meal. According to the local newspaper Monaco-Matin, a family member grew worried when Antoine didn’t show up for a family lunch at midday on Sunday, and reportedly went to Monaco’s Public Security department. A few hours later, Antoine's body was found Villa Sauber, one of the principality’s best-known cultural landmarks.

Monaco’s prosecutor general confirmed to Monaco-Matin that after the body was discovered. Investigators reportedly reviewed security camera footage, which allowed them to identify a person who had been near the scene. “We then had to modify the procedural framework in order to detain this person, place them in police custody and try to clarify the circumstances of the death," the prosecutor told the paper.

Prince Albert and Princess Charlene continue a special Monaco tradition, with Princess Stéphanie playing a key role© Arnold Jerocki
Prince Albert and Princess Charlene earlier this year

What remains unclear is that person’s role. Officials haven’t said whether the individual is a suspect or a witness brought in to help investigators piece together what happened. The cause of Antoine’s death hasn’t been disclosed.

The Prince’s Palace announced the loss in a statement on Monday. “Their Serene Highnesses Prince Albert II and Princess Charlène were saddened to learn of the death of Antoine de Massy, aged 29, the grandson of Princess Antoinette, the elder sister of Prince Rainier III,” it read. 

“A keen tennis player, he was part of a family history closely linked to the sport in the Principality. Their Highnesses share in the grief of his family and loved ones and offer them their sincere condolences at this painful time.”

Monaco's leading tennis family

Prince Albert and Princess Antoinette of Monaco alongside family members in 2005© Getty Images
Prince Albert and Princess Antoinette of Monaco alongside family members in 2005

Tennis runs deep in the family. Antoine’s grandfather, Alexandre-Athenase Noghès, was a Monegasque tennis player who married Princess Antoinette. His aunt, Elizabeth-Ann de Massy, ran both the Monte-Carlo Country Club and the Monegasque Tennis Federation until her death in 2020. Today, her daughter and Antoine’s cousin, Mélanie-Antoinette de Massy, leads both institutions as well as the Rolex Monte-Carlo Masters.

Antoine picked up a racket almost as soon as he could hold one. In a 2012 interview with L’Uomo Vogue, he recalled that his father had introduced him to the game when he was three years old. He later left Monaco for Florida to pursue intensive training alongside his studies, and he spoke of his admiration for Novak Djokovic and his ambition to one day represent Monaco at the Olympic Games.

He was the son of Baron Christian de Massy and Cécile Gelabale. His father is the son of Princess Antoinette, Prince Rainier III’s older sister, and a first cousin of Prince Albert II, which made Antoine the sovereign’s first cousin once removed.

Prince Albert II of Monaco (L) and Princess Charlene of Monaco (R) arrive to attend a meeting called "At the Roots of Europe: For Peace and Unity" in 2026© AFP via Getty Images
Prince Albert II of Monaco (L) and Princess Charlene of Monaco (R) arrive to attend a meeting called "At the Roots of Europe: For Peace and Unity" in 2026