What is Telegram, why was its CEO arrested in Paris?

FILE - The logo for the Telegram messaging app is seen on a notebook screen in Munich, Oct. 17, 2022. FILE - Pavel Durov, Telegram co-founder and CEO, shown in a file photo taken on Aug. 1, 2017.

Pavel Durov, the founder and CEO of the popular messaging app Telegram, was arrested in Paris over the weekend over allegations that his platform is being used for illicit activity such as drug trafficking and the distribution of child sexual abuse images.