The amendments to France’s 1977 law on polling, put forward by senator Hugues Portelli (pictured) of the centre-right UMP, aim to promote “sincerity” in political debate.

But Esomar warns that banning incentives would hurt response rates, while making pollsters publish full details of their weighting methods would require them to reveal sensitive information and could allow politicians to misrepresent or discredit polls unfairly.

As for the proposed ban on incentives, Esomar said, “it appears that the French government is unique in considering such a ban”. The use of incentives “is common, even necessary when using the internet for data collection, given the culture of internet users”.

Under the new rules, polling companies would have to submit their precise weighting criteria to France’s polling regulator, which would then publish them online.

The proposal has been adopted by the Senate and is due to be considered by the legal commission of the National Assembly next month.

Esomar says companies should say whether they have used weighting in their surveys, but are not required to set out in detail the method used.

The requirements of the new proposal, it says, go beyond the Council of Europe’s recommendations, which call for pollsters to publish details alongside their surveys including the population represented, the sample size, the date the survey was carried out and the methods of sampling and data collection. Further details such as the wording of questions and the identify of the client should be made available on pollsters’ websites.

In a submission to the French parliament’s legal commission, Claude Bénazeth of Esomar’s professional standards committee urged lawmakers to allow the matters in question to be dealt with by self-regulation. He pointed out that the self-regulatory regimes in the US, the UK, Germany and the Netherlands are in line with Esomar’s own guidelines on methodological disclosure. Even in Spain in Italy, where opinion polls are regulated by law, there is no requirement to publish detailed information on weighting, Bénazeth said.

France’s next senatorial election is due to take place in September this year, with elections for the presidency and the National Assembly set for 2012.