Finally I managed to combine "being in the area" and "having some time" to attack this series. Mindful of the fact that winter should be here soon (although I was in shirt-sleeves today), I decided to start at the top of the hill with caches #3 and #4.I parked at panneau 11 and set off in descending order. There were a couple of fire trucks at the start, which I assumed were there for an exercise. Their crews were gathered close to panneau 10. As I approached, I was going to give them a cheery "bonjour", but something stopped me. Just as well... this was no drill. There were several unhappy-looking paramedics, a very unhappy-looking lady walker, and a stretcher with somebody on it - not moving - with their face covered... 
Fortunately panneau 10 was just out of sight of this, so I noted the numbers and made myself scarce. Once I'd gathered the other clues, I saw that the final location wasn't very far from the start. So I approached from the east and bushwhacked the last 100 metres, to avoid the scene. From the cache, I could see that the Gendarmerie had now arrived. I walked away discreetly, preparing to tell them that I'd been "biocaching"™, but they were lost in thought. I hurried on to the next cache...
In: TB "Packy".
Nick