It is a 3.2 Mbytes files but the problem was elsewhere. I did not work with layers, but the default one on which I worked was inadvertantly locked. Thanks for pointing out the problem.
Balad

Hi, I am unfamiliar with Inkscape and new on this forum. The svg file on which I was working stopped abruptly to be editable. No feature can be seized or created. I re-installed Inkscape, no difference. "Unlock all" (déverrouiller tout) made no difference. How can I make this file editable...