Can you paint without getting paint on the floor in spite of laying down tarps, or accidentally kicking over a can? I cant so I would paint first. Depending on what floor finish you have it does take a while for it to cure and acheive maximum hardness, so if youre dragging ladders around and people walking all over, even if you have a tarp down the finish could get marred. You should be able to have a sense of what your floor color will look like and choose wall color accordingly before floors are refinished - perhaps create stain samples if floor color is to change or you cant visualize it.

Get the floors refinished first. There is a good chance that the floor refinishers will cause a little bit of damage on the walls. Once the floors are good and dry, then, you can cover them, and do the painting. They may remove the baseboards when they refinish the floors. However you can paint the ceilings, and the window trim, etc before the floors are refinished.

We need a bit more info . Is this a renovation or new build? I honestly like choosing wall color after flooring is in since that floor has a huge effet on what you choose for wall color. Drop cloths are used all the time for painters not a big deal. I aslo suggest you make sure all the lighting is the same to make this choice a bit easier I lke LED 4000K but if you like something abit warmer 3500K works just make it all the same.

I have chosen the colors. The question is what is better first? Doing the floors or paining?

The baseboard isn't typically removed for floor refnishing - the quarter round is.

I vote for paint first.

My feeling is paint first. If the floor finisher knocks the wall a bit fresh paint is easier to touch up than removing paint drippings and slop.

Do you mean refinish floors as in they are wood that's getting stripped, sanded, finished? If so, I'd do the floors first, they can be pretty messy or kicking up dust in ways you might not want to potentally have settling onto freshly done walls. It's easier to protect a fresh floor with a dropcloth than keep refinishing dust off walls.

https://www.thespruce.com/paint-walls-or-refinish-floors-first-1822179

Brazilian cherry floors stripped stained etc. The whole shabang

I would do the floors first, since they will likely have to remove the baseboards to refinish. Then they can put the baseboards back and your painter can do all the trim at the same time.

I would never refinsh floors without removing the baseboard so I stand do the floors first.

When we had our floors sanded and refinished, we did it LAST. And had an arrangement with our painter to return to the house and repair any minor scuffs. BTW, our baseboards were NOT removed during the process as the edges of the floors were hand sanded to the quarter round. I know. I watched.

My contractor just told us that they always do the floors last. I didn't ask why. But I can attest to the need for curing time. My neighbors did a gut reno and the floors got screwed up from movers' hand trucks because the floors hadn't cured enough.