This film starts out like a lot of espionage thrillers: an innocent man witnesses a murder and finds himself mixed up in a deadly intrigue of spies and counter-spies. A movie of this sort can easily become infuriatingly complicated or just plain silly. At worst it can be both, as for example Jacques Deray's earlier spy thriller "Avec la peau des autres", which also starred Lino Ventura.
"Un papillon sur l'épaule" works better because it never fully gives up its mystery. We know that something sinister is afoot and we can make some intelligent guesses, but the thing is never spelled out for us. Lino Ventura is like Alice (a paunchy, middle-aged Alice) who tumbles down a rabbit-hole and wakes up in a world that's not quite the same as before, where no-one believes him or can explain what's happening and where innocuous-looking strangers suddenly take on a menacing significance.
The white rabbit of this particular looking-glass world is played by Claudine Auger, a slinky spy who keeps whizzing up in a battered car to dispense gnomic advice and warnings. Paul Crauchet, who acted with Ventura nine years earlier in Melville's "L'Armée des ombres", plays a lunatic in pyjamas with an imaginary talking butterfly on his shoulder and a scarecrow in his bed.
It sounds bizarre and it is, but I liked it. Ventura, who starred in plenty of espionage thrillers in his career, is believable and sympathetic; the Spanish locations are used to great effect; and Jacques Deray's assured direction feeds the suspense and paranoia, his camera peering around corners and through doorways and windows (one murder is witnessed through revolving doors). An enjoyable thriller and a must-see for Ventura fans.
