News reports of the primaries to choose a Socialist candidate for the 2012 presidential elections, the Socialist success in elections to the Senate and even the scandal involving Dominique Strauss-Kahn and a maid in a New York hotel room have been counted as coverage for the Socialist party.
"We have decided to give notice to BFM TV, i-télé, LCI, Europe 1 and France Inter," said CSA spokeswoman Christine Kelly on Wednesday.
"It's not a sanction, just a reminder of the law. The three news channels and two radio stations have not respected the principle of balanced political coverage."
The CSA report found that news channels BFM TV devoted 56 percent of its coverage to the Socialist opposition with just 39.5 percent to the governing UMP party. 24-hour news channels i-télé and LCI gave 56.5 and 53.5 percent of coverage to the Socialists.
Coverage of the many other political parties shrank to between 3 and 5 percent.
"The Front de Gauche, the MoDem and the Front National were almost zapped right off our screens," said the president of the CSA, Michel Boyon, referring to three of the smaller parties.
"We just reflected what was happening in the news," said Guillaume Dubois, head of information for BFM TV. "We'll take note of this decision but we find the rules a bit rigid."
The offending outlets will not be fined and the CSA said "the counters will be reset to zero" for the final quarter of the year.