Hello, I would like to define a priority order between the background and the outline of a shape. Currently inkstitch will start with the outline and then do the background (fill), but I would like it to start with the fill and then the outline.
Do I have to use 2 different objects for this or is there an option?

Thanks to you!

Actually it is the other way around, but the params dialog is not very reliable on that. Use the simulator to see the correct order. It is possible though, to turn the order around by setting a param manually (inkstitch:stroke_first).

But it's better to use two separate objects. This will enable you to transform the shapes for pull compensation.

Thanks for you answer but, How can i set this param manually ? 

First: if you want the fill first and then the stroke you are already good and don't need to manually set any param (although the params simulator may show it the other way around - check the real simulator to see the correct order of the stitch plan).

Second: I would really recommend to use two separate shapes to avoid registration issues when sewing

If you still want to set the param:

Open the xml editor in Inkscape (Shift + Ctrl + X). Select the element which has both a running stitch and a fill and make sure the editor displays the attributes (there is a switch at the bottom of the dialog). Click on the plus symbol to add an attribute. Write embroider_stroke_first and set it to True (this will then do the opposite of what you asked for above:  first stroke and then fill). Ink/Stitch will then transform this attribute to inkstitch:stroke_first. You could also type that directly, but this may cause namespace issues.

Indeed, once the embroidery is launched it starts with the filling, surprising that on the preview it does not show me so ^^
But thanks for your explication :)