> size:90>Creux ...<size:45><br>Entrée ?

I have had this problem with point label, and discovered that the line spacing resulting from <br> is set by the -scale parameter, and not any formatting defined within the string.

Probably -scale won’t work for a map title.

Try using <thsp> (thin space) instead of <br>.  If it works it is easiest.

Some more information on drawingchecklist [Therion wiki] - points

Another way is to use these inside a code tex block.  Perhaps has the same effect as -scale, but for various elements of the default header.

#Legend Text size.  Uncomment to customise default header text sizes

     \legendtextsize={\size[12]}                  % legend text default 12

     \legendtextsectionsize ={\size[14]} % subheading default 14

     \legendtextheadersize={\size[26]} % heading text default 26

You could make the heading text default size smaller, thereby reducing the size of the linefeed due to <br>, and use <size:45> to make the lettering larger or smaller.

Bruce