Thanks Jobigoud,
My script already get the camera info and it works fine but I have to run it each time I select a new render target which is not useful.
To be more clear on my wishes, each time I select a render target I would like an object to be automatically placed at the camera position without any action (I mean not running the script manually).
As I'm using a sphere around the camera in combination with a sphere surrounding the scene to created fog, the sphere around the camera should be placed at it's position when I start render.
Indeed the batch render job may help as the start render could be triggered but I usually render interactively and if I often miss the sphere placement and I should restart everything ...
It's not a big issue but would be cool to enhance my script with this feature