So, the FT says (Thorny issue of immunity tests IMF) that while the IMF's articles of agreement don't give Strauss-Kahn immunity outside actions in his official capacity (Article IX, Section 12), The Convention on the Privileges and Immunities of the UN (pdf)* does say that the Secretary General and Assistant Secretaries General get full diplomatic immunity.

This is probably all moot anyway because, as the FT says: “However, it is almost unthinkable that the IMF would make a move to exploit this legal anachronism of providing blanket immunity for an international official,” said Mr Kurbalija. “The laws of diplomatic immunity need to be synchronized with the values of our time.”



*I recommend taking a glance at this document even if you're willing to take my summary on trust, just for the gloriously, gloriously inappropriate use of comic sans.