Telecommunication giant Deutsche Telekom, carmaker BMW and several other major German companies have stopped advertising on rightwing US news and opinion website Breitbardt due to concerns about its content.

Breitbart has enjoyed global attention and scrutiny since its former chair, Steve Bannon, was made Donald Trump’s campaign chief and later his chief White House strategist.

The media baron has branded Breitbart the platform for the “alt-right”, the new extreme right-wing movement with links to white supremacist ideology.

The German boycott, prompted by a social media campaign titled KeinGeldFürRechts, which translates as “No Money for the Right,” follows a similar decision by Kellogg’s in the US, to which Breitbart responded by urging readers to no longer buy the cereal firm’s products.

The restaurant chain Vapiano and supermarket chain Rewe have also joined the boycott against the pro-Trump news site.

"The positions held by Breitbart.com contrast with Vapiano's values, such as openness and tolerance," Vapiano, the restaurant chain offering Italian food across Europe and the US, told AP.

Deutsche Telekom, the parent company of wireless carrier T-Mobile, said it “absolutely does not tolerate discriminatory actions or statements”, confirming its adverts had not been placed intentionally on the website.

The decisions come as Breitbart plans to open sites in France as well as Germany as the country prepares for elections next year amid high tension over the migrant crisis.

Breitbart's reporting, although defended as satire, has been branded misogynistic and racist

Last month, the far right in France extended its welcome to the ultra-conservative news website.

Marion Marchechal Le-Pen, the niece of Marine Le Pen, the leader of the National Front party, voiced enthusiasm for Breitbart giving her party’s supporters new voice in France.

Breitbart previously stated that advertisers would be unwise to boycott the site because it has a loyal following of 45 million readers.

According to the Pew Research Centre, nine per cent of the general news audience in the US visits the site.