Creepiest Passenger Ever? Man Accused Of Groping Sleeping Woman In First Class — Then Came The Note

A 48-year old Frenchman flying SWISS from Zurich to Miami on April 28 is accused of abusive sexual contact – touching another passenger’s lower back in a way designed to look accidental while she was sleeping, repeating it longer to test whether she woke, and then using a “submarine” hand motion apparently trying to get under her clothing or between her legs.

The man and 29-year old woman are said to have been traveling in first class on Swiss flight 64. This surprises me. The seats don’t seem open enough or close enough to facilitate the kind of contact being described, and often even a charging document might mix up business and first class (or even premium economy, since that’s like domestic first).

The two had briefly exchanged pleasantries at the start of the flight, according to the complaint, then she turned away, curled up and went to sleep. She wouldn’t need to curl up in first!

• A flight attendant, alerted by other passengers, approached and apparently saw the man’s hand on the woman’s crotch over her jeans, making what was described as a scooping or rubbing motion. He was questioned and since he couldn’t provide indication to show he knew the woman (it still wouldn’t have been appropriate in the cabin) he was moved to coach to separate them.

• When she was woken up and told what had happened, she confirmed she didn’t know him and began shaking and crying.

• Later, the man was brought back into the cabin to collect his belongings and he allegedly tried to pass the woman a note reading, “You look beautiful when you are sleeping.” When he was interviewed by law enforcement he still had the note on his business card that said she looked cute while asleep. He’d already been called out, did he think she was going to swoon over this?

• On arrival, after clearing immigration, investigators taped an interview with him. He reportedly declined assistance from the French consulate, said nothing happened, but after being told there were eyewitnesses and video evidence he admitted touching the woman and said he “did not think it was such a big deal.”

When told witnesses saw contact with her genital area, the report says he explained that he touched “whatever he could reach from across the armrest” and admitted taking photos with his phone – but deleted them before law enforcement could inspect them. (I would expect that his phone would have been taken for forensic examination.)

His pretrial detention hearing was scheduled for today. Prosecutors argue that he’s a flight risk and danger to the community and do not want him relesaed. He’s charged under 18 U.S.C. § 2244 which covers knowing sexual contact without permission in federal jurisdiction, including intentional touching, directly or through clothing, of genitalia, groin, buttocks, inner thigh, breast, etc.

Since this occurred on an international flight to Miami, it’s covered by 49 U.S.C. § 46506, applies the law to acts on aircraft in the special aircraft jurisdiction of the United States (including foreign aircraft outside the U.S. whose destination or original is in the U.S.).

48-year-old French national Guillaume Sebastien Roger Mattler has been charged with sexually assaulting a sleeping 29-year-old woman on a Swiss International Air Lines flight to Miami,

he allegedly slipped his fingers beneath her clothing and made a scooping or "submarine"… pic.twitter.com/XdcLfAgDbG

— G R I F T Y (@GriftReport) May 4, 2026

It seems colloquially that he might just plead to being French? Because, really, the facts don’t look good for the defense here. There are multiple eyewitnesses, a passenger reportedly taking videos, a flight attendant apparently seeing his hand on the woman’s crotch over jeans, and a note saying she looked cute while sleeping (creepy) plus his post-flight admissions, and deleted photos.

So his lawyer is probably just looking to suppress some of the admissions, force the government to prove the exact nature of contact, and hope for a decent plea deal I guess. (He was plausibly in ‘custody’ when he was interviewed after immigration processing, may not have been properly Mirandized, and can claim that being French he may not have fully understood the questions and wasn’t clearly waiving his rights.)

This man seems to be among the creepiest passengers ever, though we’ve seen this kind of behavior behavior before. What is truly unique here is the degree of difficulty, if the passengers really were seated in the Swiss Boeing 777-300ER first class cabin. There’s just no subtle way to do what he was trying to do, angling over the seats. Most of the time this happens it happens in coach.