Strauss-Kahn, the former head of the International Monetary Fund who is facing attempted rape charges in New York City, showed up at a high-profile Paris birthday party for prominent Socialist Julien Dray, France 24 reported.
On Sunday, Hollande distanced himself and his campaign from Strauss-Kahn, who was once prominent in the Socialist Party and a potential presidential challenger, saying he "no longer has a role in political life."
Hollande's campaign chairman, Pierre Moscovici, his communications director, Manuel Valls, and his former partner and 2007 presidential contender, Segolene Royal, all said they left the party when they heard Strauss-Kahn was on his way.
Valls said Strauss-Kahn was no longer linked in any way with the Hollande campaign, and "has no reason to come back into it."
Royal said it was "out of the question" to see Strauss-Kahn in person, "in the name of women's rights and respect for women."
Meanwhile, French President Nicolas Sarkozy, who is hoping to be re-elected in the second round of voting May 6, called out the Socialist Party for "hypocrisy."
"Just months ago, the whole Socialist Party was hoping for a candidate named Dominique Strauss-Kahn," he said in a TV interview. "There's no shame in being friends and defending your friends … but you need to own up to it. What's troubling in all of this is the deception, the hypocrisy and the lying."