Am 11.03.2014 um 23:13 schrieb Fabrice <couvreur.fabrice@wanadoo.fr>:

> Hi,
> I'll try to rephrase my question. In fact, the title is not in bold and the size of the font is not taken into account.

When you want to use a sans serif font you should also set one which isn’t the case in your setup.

\loadtypescriptfile[mathdesign]
 
\definetypeface [mainface] [rm] [serif] [palatino] [default]
\definetypeface [mainface] [tt] [mono]  [modern] [default] [rscale=0.9]
\definetypeface [mainface] [mm] [math]  [xits] [default]

\setupbodyfont[mainface,11pt]

Wolfgang