How to change the background color of the page

@Rwann31 d'après ce que je comprends, tu sembles francophone. Même si les réponses à tes questions ont déjà été données, tu peux aussi poser tes autres éventuelles questions en français, si ça peut t'aider.

The only solution I found was to create un color rectangle witch hide the markers.

If by markers, you mean things like page numbers and other parent page items, then make a layer for the markers. Make sure it is the top layer of your document. Make a bottom layer for the base page color rectangle. Lock both of those layers, and use central, unlocked layer(S) for the rest of your content.

I'm not sure exactly waht you are trying to do. If you plan on printing on colored paper you can edit the [Paper] swatch to simulate the paper color.

If you are printing on regualr paper without a color, then you must, as you've learned ass your own background color object. As Frans has mentioned, it's best to do this on a Parent/Master page. I also recommend making a separate layer for backgrounds and locking it so you don't accidentally use the background frame as a text frame by clicking in it.

Well, that is what Parent pages are for 😉

Let me offer a little tip that may make life easier or you:

Select your background with your Selection/Black Arrow tool. Then move near the bottom of the InDesign Toolbar to the bent double-arrow that signifies the Swap Fill and Stroke toolbar shortcut. You can also use the keyboard shortcut Shift+X to swap the fill and stroke for selected object(s).

Most backgrounds don't have a stroke set around them. If you set yours without a stroke value, swapping the fill and stroke will (momemtarily, temporarily) let you switch that background frame to have a background stroke of your background color and a fill of [None]. You can then toggle back and forth as you need to work with your guides, margins and other elements contained within the background frame.

It's not the perfect solution, but this trick should work quickly, easily and effectively for you.

Hope it helps,

Randy