Anne Sinclair was to give her first news conference since last year's scandal, in which her husband faced down two sexual assault allegations, later in the morning to promote the ambitious new site.
Sinclair, a leading French journalist even before International Monetary Fund director Strauss-Kahn resigned last year, and speculation over her relationship has added to the buzz surrounding the new project.
Sinclair, a multimillionaire heiress and former television anchor, stood by her husband. Charges that he attacked a New York hotel maid have been dropped, but he has been dogged by a string of further allegations.
The site went online early Monday, closely modelled on its US parent, with the same design and logo but with a distinctly French mix of opinion columns, aggregated news content and interactive news features.
"Le HuffPo" is a partnership between the leading French daily Le Monde, the US parent firm and banker Matthieu Pigasse. It incorporates a former French interactive news website, Le Post, owned by Le Monde.
Huffington launched her original American website in 2005 and sold it to Internet giant AOL in 2011 for $315 million (246 million euros). It boasts 37 million readers per month in the United States.
The size of the buyout surprised many observers, as the HuffPo's gossipy mix of celebrity, political and lifestyle stories was at first largely culled from other outlets and fleshed out with unpaid columnists.
It has become a major advertising platform, however, and now has British and Canadian editions. The British version has not been a hit, however, and it remains to be seen whether the formula will catch on in France.