Here is another template. I changed the blend to Multiply and added an arithmetic composite to compensate it.

De : Yann Papouin <yann.papouin@...400...>
À : Ivan Louette <ivan_louette@...1857...8...>
Cc : Niko Kiirala <niko@...1267...>;
Envoyé le : Mer 31 mars 2010, 10 h 01 min 02 s
Objet : Re: [Inkscape-devel] Re : Filter effect and blur background

Thank you Ivan, your template is exactly what I want (but I didn't change the layer blending mode, it must be normal to work properly)
See a preview here:

Artifacts can be annoying but it might be fixed later, maybe they are due to the IIR Filtering method added in 2007?

By the way, the layer with the "background property" cannot be renamed, changes are not made in the svg.