I was taking pictures of French mountains with a friend, using long exposure time, on a small path close to the town, when I saw a strange light among the clouds. I first thought it was the moon but then I remembered it was a day of new moon. Besides, it was moving slowly, back and forth laterally. I was fascinated, I did not know what it could be at all, but it was beautiful, so I took a picture. It is a 10 seconds exposure so the object is blurry because of its motion. The light around it looked unreal, as if it was a very powerful but very far object, above the mountains. That is why I thought then it was an UFO. My friend was amazed too. Gradually, the light became dimmer, and the object vanished in the dark in a few seconds. All that remained were clouds. We got home.