Fache is interrupted—against his specific orders—by a subordinate to tell him a cryptographer, Agent Sophie Neveu, is on her way to the gallery.
This is problematic for three reasons.
#1: She's a woman, her gender is automatically distracting, and Fache thinks they have no business being on the police force.
#2: She's really well educated, and uses a new British method of cryptography that drives her superiors bonkers.
#3: He told everyone that he and Langdon were not to be disturbed under any circumstances.
While Fache is having a rage stroke, Neveu approaches and introduces herself to Langdon.
She's solved the code, but first she tells Langdon that he has an urgent message from the States at the U.S. Embassy. She hands him a slip of paper with a number on it and tells him to call right away.
Fache offers his own phone to Langdon.
Robert dials, but is surprised to realize that the number on the paper is Sophie Neveu's. When he starts to tell her the mistake, she quickly tells him nope, that's the right one, just enter a three-digit code to retrieve his message.
Odd. He enters the code, and finally catches on that Sophie has left him a message on her own answering machine.
In the message Sophie tells him not to react, but that he's in danger. But don't worry; she's got detailed instructions for him to follow.