Guillaume Mattler: Man charged after alleged assault on sleeping woman during Zurich to Miami flight

A woman was allegedly assaulted while asleep on a flight, before the accused did something even more unsettling.

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Madeline Cove
The Nightly
A woman was allegedly assaulted while asleep on a flight.
A woman was allegedly assaulted while asleep on a flight. Credit: Supplied/Supplied

A passenger accused of assaulting a sleeping woman mid-flight allegedly returned to her seat with a note after being caught and moved by the flight attendant.

Guillaume Sebastien Roger Mattler, 48, is facing a charge of abusive sexual contact following an incident aboard a Swiss International Air Lines flight from Zurich to Miami on April 28, according to a criminal complaint filed in the Southern District of Florida.

Authorities allege the woman, 29, had briefly exchanged pleasantries with Mattler before turning away and falling asleep in her first-class seat.

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What followed, according to multiple witnesses, unfolded slowly — and in plain sight.

One passenger reported seeing Mattler touch the woman’s lower back, appearing to disguise the movement as accidental. When she did not wake, the contact allegedly continued, becoming more deliberate.

People reported that a second witness told authorities they saw Mattler move his hand in a “submarine” motion, as if attempting to reach under the woman’s clothing.

A flight attendant, alerted by those nearby, then approached and allegedly observed Mattler with his hand on the woman’s crotch over her jeans, making what was described as a scooping or rubbing motion.

Unable to prove he knew the woman, Mattler was moved to another part of the aircraft.

But the interaction did not end there.

After being escorted back to retrieve his belongings, he allegedly attempted to pass the woman a handwritten note.

“You look beautiful when you are sleeping,” it read.

The woman, who had been asleep throughout the incident, was later woken by the crew and informed of what had occurred.

According to the complaint, she “confirmed she did not know Mattler and was shocked,” before she “began shaking and crying.”

During a post-flight interview with authorities, Mattler initially denied the allegations.

But after being confronted with 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.”

He later told investigators “that he touched whatever he could reach from across the armrest.”

Authorities also said he claimed his intention had been to get the woman’s phone number, and produced a note written on his business card reading, “you look cute when you sleep.”

Mattler is currently being held at the Federal Detention Centre in Miami.

If you or someone you know needs help, contact 1800 RESPECT (1800 737 732), or Sexual Assault Counselling Australia on 1800 211 028, the WA Sexual Assault Resource Centre on 6458 1828 or 1800 199 888 or Lifeline on 13 11 14.

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