The move comes after the agency had placed ban on My Friend Cayla, an internet-based doll, over privacy issues.
Germany's Federal Network Agency (Bundesnetzagentur), the country's telecommunications agency, has banned the sale of children's smartwatches after it classified such devices as "prohibited listening devices".
In mid-October, BEUC has warned parents that many kids' smartwatches are plagued by security flaws that allow attackers to track children and listen to their conversations.
"Using an app, parents can use such children's watches to listen unnoticed to the child's environment and they are to be regarded as unauthorized transmitting equipment", said Jochen Homann, President of the Federal Network Agency. "Our investigation has also shown that parents have used the watches to listen to teachers in the classroom". "There is a shocking lack of regulation of the "internet of things', which allows lax manufacturers to sell us dangerously insecure smart products", security expert Ken Munro told the BBC". In the case of children's smartwatches, there is a GPS tracking system which is meant to keep the kids safe. "Using privacy regulation to ban such devices is a game-changer, stopping these manufacturers playing fast and loose with our kids' security".
Most are equipped with a Sim card and a limited telephony function and are set up and controlled via an app. It urged schools to be vigilant about the use of such smart watches.
On Friday, the Federal Network Agency said its already cracking down on sales of the smartwatches built with the listening function, which are generally targeted to children ages 5 to 12.
He called for Europe-wide measures to increase the security of such devices.