British Gas has been criticised for newspaper advertisements which remind customers that its rival EDF Energy is a French-owned company.
British Gas wants a review of the watchdog's decision
The Advertising Standards Authority (ASA) ruled that the advertisements were "denigratory" to EDF Energy.
EDF Energy, owned by French giant Electricite de France, complained that the references to its parent company were likely to confuse UK customers.
A British Gas spokesman said the ruling was "political correctness gone mad".
Two of the British Gas adverts referred to EDF Energy as "derived from Electricite de France" while a third said the company was "formerly known as Electricite de France".
Following an investigation, the ASA said the adverts breached an industry code.
It said: "We considered readers were likely to understand that EDF Energy's product and business was French. We considered the ads were misleading and denigratory and suggested the origin of the product was France."
However, the industry watchdog did not uphold complaints from two members of the public who said the adverts were xenophobic and intended to provoke racism towards France.
EDF said it was satisfied with the ruling, and stressed it was investing in the UK, keeping its call centres in the UK and had launched a final salary pension for UK employees.
A spokesman for British Gas, which is owned by Centrica, said that "no one is suggesting there is anything wrong with EDF Energy being a French company".
"Does the ASA really believe that pointing out the nationality of a company denigrates that organisation?" he added.
"We like the French. We would dearly love to sell them gas and electricity.
"Unfortunately the French government don't want a foreign company selling gas to their residential consumers."
British Gas now wants an independent review of the ASA decision.