Hi Otared and Wolfgang,
It's great, the following code does the job!
Thank you so much.
Fabrice
\useMPlibrary[dum]
\definecolor[fondpaille][c=0,m=0,y=0.2,k=0]
\setupfloats[freeregion=no]
\definetextbackground[fondpaille]
[background=color,
backgroundcolor=fondpaille,
frame=off,
location=always,
]
\showframe
\starttext
\starttextbackground[fondpaille]
\startplacefigure[number=no,location=right]
\externalfigure[dummy]
\stopplacefigure
\startitemize[n]
\dorecurse{3}{\startitem \input ward \stopitem}
\stopitemize
\stoptextbackground
\stoptext