"She has an open mind."
Translation:Elle a l'esprit ouvert.
Linguee (https://www.linguee.fr/francais-anglais/traduction/j%27ai+l%27esprit+ouvert.html) offers many examples of avoir l'esprit ouvert.
Linguee is a great source, but you have to look where the examples come from. I was once wondering about choosable and found many examples there. In a survey here I was told it is very rarely used in mathematical problems and in any case it is more the ability of something to be chosen than the ability of someone to choose this thing what the sources implied. The German usage of wählbar focuses more on the latter. Having had a closer look to the sources on linguee I found that all the examples were from German and Eastern European (maybe German influenced) web sites.
It is a set expression → avoir l'esprit ouvert means "to have an open mind".