"She has an open mind."
Translation:Elle a l'esprit ouvert.
We don't say "avoir l'esprit ouvert" but "être ouvert d'esprit".
A french native speaker contributor.
Which is close to our common English expression "is open-minded".
But it seems that Duo wants us to translate the alternative English "has an open mind" with the closer translation of "avoir l'esprit ouvert"?
Thing is nobody would ever say "Elle a l'esprit ouvert", while "être ouvert d'esprit" is always used in this case. At best it's a poorly chosen sentence to translate.
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.
Any rules about articles in those two languages, then they are different?
It is a set expression → avoir l'esprit ouvert means "to have an open mind".