Projector change color programmatically

Hi all,

I'm about to lose my mind because I cannot reach an objective.

I need to programmatically change the color of the material attached to a Projector. (in fact the projector projects a colored circle at the bottom of my player).
I used a Shader with a color defined as "_Color".

I thought I would be able to access the material using :

Code (csharp):

1.  
2. Projector proj = GetComponent<Projector>();
3.         proj.material.SetColor("_Color", Color.green);
4.  

But Unity tells me that there is no material property attach to the projector.

I read a lot of blogs and unity answer topics + unity documentation and so on.
And I'm stuck to no solution.

Please help me

Cheers !