The handshake itself should be relatively brief but firm – une poignée de main molle (a limp handshake) will do nothing to convince the other of your sincerity. Nevertheless, it shouldn’t be a bone cruncher, and the French tend neither to pump nor linger. It’s also important to look at the person whose hand you’re clasping. If you’re talking to someone else at the time, break off the conversation, verbally greet the person you’re shaking hands with and look him in the eye. There’s nothing I hate more than a man silently extending his hand in my direction while continuing to talk to (and look at) another. It gives me the impression I don’t count for very much. The double-handed shake (i.e. using one hand to shake that of someone, while firmly squeezing his forearm with the other) is normally confined to politics. In a world where the word ‘never’ usually means ‘not today’, it is not a proof of real sincerity. And placing your non-shaking hand on the other’s shoulder, or using it to pat or slap him on the back are also not guaranteed to convince – though a previous Président de la République did frequently resort to both.