Mr Delcroix said: "We often criticise teenagers for their online behaviour, but parents are no better."
He said that people should think about how their children will feel later in life about images of them as infants or adolescents being posted on Facebook or other social networks. "Children at certain stages do not wish to be photographed or still less for those photos to be made public," he told Le Figaro newspaper.
The French police recently renewed warnings about the danger of paedophiles targeting children after seeing family photographs online. Some parents have been forced to remove naked pictures of babies or young children from social networks.
Jay Parikh, a vice-president of Facebook, said the service was considering setting up a system to notify parents who put photographs of children online without restricting their privacy settings.
Mr Parikh said: "If I was putting online a photo of my kids playing in the park, and I accidentally shared it with everyone, the system could say: "Hey, wait a minute, this is a picture of your children. Usually you only send them to members of your family. Are you sure you want to do this?"'
The French Gendarmerie has placed a warning to parents on its Facebook page: "Posting photos of your children on Facebook is not without danger... Protect your children!".
The Gendarmerie also advised parents to beware of "chain" posts on Facebook with messages such as: "Are you proud of your children? If so, post three pictures of your beautiful children on Facebook and get 10 of your friends to do the same."
The police fear that pictures of children may end up in the hands of paedophiles or criminals who could use them for identity theft.