Obtain the same render in 3D and 2D ?

Maybe that's kind of a rookie question but here we go...

I made a 2D-iso game ("false 3D") that I recoded to be true 3D, because spritesheets were becoming too complex to manage. Long story short, I would like the real-3D game to have more or less the same visual aspect as the 2D-iso game.

Basically, I took the 2D textures and put them on my 3D meshes. For example, the "ground" bitmap was applied as a texture to the plane that's used as the 3D ground.

I would like those textures to look as they looked in the 2D game, but I don't know how to do it with lights and diffuse emissions and so on... for example the ground looks either too desaturated or too contrasted, it's never right...

Is there a "standard" configuration to have the same visual aspect ported from 2D bitmap to 3D texture ?