France, Sept. 18 -- The Paris prosecutor's office said it had recently launched at least one investigation linked to a social media trend involving the devices. Prosecutors did not identify the make of glasses involved.

Smart glasses combine conventional eyewear with cameras, microphones and, increasingly, artificial intelligence.

Several models are available, although glasses produced by US technology giant Meta with Franco-Italian eyewear group EssilorLuxottica dominate the market, accounting for an estimated 76 percent of global sales.

Meta's AI-enabled glasses contain a small camera that allows users to take photographs and record video discreetly. Around seven million pairs were sold last year, while EssilorLuxottica has reported ...