‘Not such a big deal’: French man sexually assaults sleeping woman on Miami-bound flight, reveals his shocking intentions after being confronted by authorities

A disturbing case of alleged sexual assault has emerged aboard a Swiss International Air Lines flight, where a 48-year-old French national is facing a federal charge of abusive sexual contact after allegedly assaulting a sleeping woman seated next to him in the first-class cabin on a flight from Zurich to Miami. According to a federal complaint, witnesses reported seeing the man touch the 29-year-old victim and recorded video of the incident, prompting a flight attendant to intervene and separate them.

Authorities say the woman, who did not know him, was left shaken after being awakened and informed of what happened, while the suspect later admitted to touching her after initially denying any wrongdoing. The suspect was identified as Guillaume Sebastien Roger Mattler. He allegedly sexually assaulted the woman on the Miami-bound flight on Tuesday, April 28, 2026, WPLG Local 10 reported, citing a criminal complaint.

After the incident came to light, Mattler is facing one count of abusive sexual contact, according to a complaint filed in the Southern District of Florida on Wednesday, April 29, 2026, the news outlet reported. He is being held at the Federal Detention Center, Miami, according to prison records viewed by PEOPLE. The complaint against Mattler states that while Mattler was a passenger on SWISS AIR LX64 from Zurich to Miami, he allegedly assaulted the woman seated next to him in the flight's first-class cabin.

Witnesses intervene, alert flight attendant

The incident was witnessed by at least three people, including a flight attendant. An FBI agent wrote in the complaint that two passengers noticed Mattler touching the woman as she slept, WPLG Local 10 reported. According to the local news outlet, one witness “took several videos on his cell phone” while his friend became “very concerned and went to find a flight attendant.” The witness saw the two “exchange pleasantries” briefly before the victim “turned her back, curled up in the seat and went to sleep,” PEOPLE reported, citing the complaint.

Later, the same witness reportedly saw the suspect touch her lower back, seemingly trying to “make it look like his hand slipped from the armrest.” After the victim did not wake up, the suspect touched her lower back again and held it there "for a longer" period, as stated in the complaint.

“Witness 2 observed Mattler moving his hand in a ‘submarine’ motion, as if trying to get his hand under the victim's clothing and/or between her legs,“ FBI Special Agent Peter Ganzert wrote in the complaint. Authorities claimed that the flight attendant approached Mattler and the woman and saw him “with his hand on (her) crotch, over her jeans, making a scooping or rubbing motion on her vagina.”

The flight attendant was alerted by witnesses, prompting them to “approach the seat where the victim was sleeping.” They observed “Mattler with his hand on the victim’s crotch, over her jeans, making a scooping or rubbing motion on her vagina."

The complaint also states that Mattler provided no information indicating he knew the woman and that the flight crew moved him to coach to separate him from her. He was later escorted back to grab items he left behind, when he attempted to pass the victim a note that read, "You look beautiful when you are sleeping,” according to the complaint.

The victim was left in shock after the attendant woke and informed her about what had occurred. According to the complaint, she “confirmed she did not know Mattler and was shocked.” She also “began shaking and crying,” WPLG Local 10 and PEOPLE reported.

What the suspect told authorities

Mattler initially denied touching the victim in a post-flight interview with authorities after he was processed through immigration. After authorities confronted him with multiple eyewitness accounts and video evidence, he admitted “that he touched the woman sitting next to him and that he did not think it was such a big deal."

After an official said a witness saw him touch the victim's “vaginal area,” Mattler also stated that “he touched whatever he could reach from across the arm-rest,” per the complaint.

FBI Special Agent Ganzert wrote in the complaint that Mattler initially claimed he touched “her lower back and upper buttocks,” but after being informed that witnesses saw him touching her genital area, he stated, “he touched whatever he could reach from across the arm-rest.”

Mattler admits his intentions

In the interview, Mattler told authorities that “his initial intention was to get the woman's phone number and give her his,” news outlets reported, citing the complaint. “He then provided the note from his pocket that was written on his business card that read 'You look cute when you sleep,' along with the flight information and his seat number.”