The digital call to arms came shortly after the first round of the French presidential election.

On an online message board frequented by extremists in the United States, an anonymous user last month urged others to bombard social media sites in France in support of Marine Le Pen, the far-right French candidate, by using memes, hashtags and other digital tricks that they successfully employed during last year’s American presidential election. Within days, the online thread — and similar discussions across the internet — was flooded with hundreds of users in the United States offering to help the digital campaign.

But the American tactics have not translated overseas.

Despite such efforts, the far right in the United States and elsewhere has so far failed to reach much of the French electorate ahead of the country’s vote this weekend, according to a review of social media activity done for The New York Times. The analysis, which was based on a review of millions of Twitter messages related to the election since last summer, showed that more than one-third of posts linked to certain political hashtags originated from the United States, although few went viral in France.

“There’s a big cultural gap that these groups have to jump over to expand their message,” said Ben Nimmo, a senior fellow at the Atlantic Council, a think tank, who has studied the far right’s recent efforts in France. “The language and iconography of the alt-right is pretty specific. Most of it just isn’t going to translate well.”

The French presidential election is the latest front in the digital assault by the American far right or alt-right, a diverse and loosely connected group of internet-based radicals who have garnered attention by using memes — online satirical photographs with often biting captions — and other tactics to further their views worldwide. The activists, a combination of white supremacists, anti-Semitic campaigners and other far-right types, were closely linked to the presidential campaign of Donald J. Trump, although the extent of their influence remains unclear.