The International Monetary Fund boss who opinion polls had pegged as the strongest likely challenger on the left to unseat conservative President Nicolas Sarkozy, was charged on Sunday with sexual assault on a New York hotel maid.

“The news we received from New York last night struck like a thunderbolt,” Aubry said in a statement. “I call on the Socialists to stay united and reasonable,” she said, noting it was vital to respect the presumption of innocence.

Aubry is widely expected to run in the Socialist Party selection contest to pick a presidential candidate, along with veteran leftists Francois Hollande and Segolene Royal who have already declared their candidacies.