I use an open type font with three typographic variants. In CSS I can choose a variant like this:

@font-face {
  font-family: "My Font";
  font-feature-settings: "ss01" 1;
}

But this doesn't work with Prince. So I found some hints with prince-opentype and tried this:

@page {
  font-variant: prince-opentype("ss01" 1);
}

But it doesn't work either.

How can I choose a typographic variant in Prince?

Ok, I found the solution. First it was not written like CSS and also I must set it to alle elements and not (only) to the page:

@page, * {
  font-variant: prince-opentype(ss01(1));
}

Yes that's it, although @page can't be combined with element selectors like that and will be ignored.