The European Commission has warned participants in its emissions trading scheme (EU ETS) not to respond to requests for account registration information from a Brussels-based company, the Commission said on its website.
"We understand that operators have received requests for account registration information from a company called European Climate Registry," the EU Commission said in a statement.
"This company does not form part of the EU ETS registry system and registration with the European Climate Registry is not in any way a requirement under EU ETS legislation."
European Climate Registry did not respond to email request for comment.
Emissions registries administer carbon permits under the EU ETS, which caps the emissions of heavy industry like cement and steel companies and forces them to buy permits to cover excess emissions or sell them when emissions are reduced.
The Commission first warned participants about the European Climate Registry in 2009.
The German emissions registry on Monday told the Commission its members had received more unsolicited emails from the firm requesting they register on its website.
A Commission spokeswoman told Point Carbon News the Commission had also taken the first steps to start an investigation into the European Climate Registry website with a view to possibly taking legal action.
On its website, the firm calls itself "the sole pan-European database and direct trading service for account holders of nationally registered accounts for greenhouse gas emissions."
It charges users an activation and maintenance fee of EUR1512 ($2,016) a year, followed by an installation fee of 144 euros per account, according to its website.
Participants in the EU ETS are on high alert after 1.6 million carbon permits went missing from the Romanian registry account of cement manufacturer Holcim last month.