Hello,
Currently I find myself facing a real problem with a material corona (you will be able to see it in picture and will be surrounded).
I want to point out that this material has no reflection and that this problem comes from putting two objects side by side and have the same material
It’s been two days since I took my head to find a solution and nothing to do, yet I tried everything.
Someone would have an idea please?
Thank you 
use rayswitch material same material for direct slot and more darker for GI. this will remove light bounce
I will try your solution and I’ll let you know
Thanks Jpapers
This is called global illumination. 
One idea would be to lower the albedo (brightness) of the white paint material, however you will probably always end up with some light being bounced.
Another would be to lower the max sample intensity in performance tab to 10 or 5, but not lower - this will help, but will affect the global illumination in the whole scene.
Last resort is using the rayswitch material as already suggested. So you use the bright material for direct visibility, reflections, and refractions, and something darker or purely black for the GI.
Just put a darker material on a plane on the top part.
Thank you for your answers
