A well-to-do couple were arrested for murdering then char-broiling their French nanny — after neighbors reported a “weird barbecue” smell to cops and the au pair’s scorched body was found in the backyard of their posh home, according to reports.

French-Algerian designer and makeup artist Sabrina Quider, 34, and her boyfriend Ouissem Medoun, 40, were collared for killing Sophie Lionnet, 21, in London on Friday, the Guardian reports.

Cops found Lionnet’s remains outside the ritzy $1.2-million residence on Wednesday after neighbors spotted them starting a big fire — but it didn’t smell like they were grilling burgers.

“My young son called out, ‘If you are having a barbecue, are we allowed to come?'” one neighbor told the Daily Mail.

“I told him, ‘no that’s not a barbecue, that’s a bad smell.’ I thought they may be burning leaves.”

The body was so badly burned that cops couldn’t initially tell if it was a man or a woman, according to the paper.

Lionnet had been living with the family for a little over a year, caring for Quider’s 3-year-old daughter and 6-year-old son — whose dad was a member of Irish boy-band Boyzone, according to reports.

But the nanny was apparently miserable and had been scheduled to return home Monday — but never arrived, a friend told the Telegraph.