@iergo https://github.com/tsproisl/textcomplexity
Ça marche en anglais et en allemand, mais certaines mesures peuvent aussi être appliquées au français
"All surface-based, sentence-based and dependency-based complexity measures are language independent. Some of the constituency-based measures are also language independent, but most rely on the NEGRA parsing scheme, i.e. can only be applied to German data."