"We sent a letter of formal notice to Yahoo yesterday" so that it will stop publishing articles from Belgian newspapers on its search engine without prior authorisation, said Bernard Magrez, lawyer for the editors group Copiepresse.
Copiepresse accuses Yahoo of violating copyright laws by giving Internet users access to archived newspaper articles which the papers themselves would now charge people to read.
While its makes no threats in its letter, Copiepresse could take legal action if it is not satisfied with Yahoo's response.
A year ago, Copiepresse took Google News to court in Belgium to stop it reproducing content from French-language and German-language newspapers in Belgium on its Belgian website.
On September 5, a lower court ordered the California-based company to desist, and said it would face a daily fine of one million euros (1.
3 million dollars) if it did not comply with the ruling.
Google has appealed the decision and a verdict is expected by the end of the month. T