Board Thread:Improvements and Issues/@comment-4725729-20150810191246/@comment-5398287-20150810234047

Sternritter M wrote: There is no evidence that Giselle is male other than Yumichika's comments, and that cannot be considered any proof. For all we know Kubo did that just to troll us.

Giselle looks female, behaves female and considers herself to be female. I'd say she remains female until Kubo states otherwise. I'd agree with you, but a while back there was an end-of-chapter overview on some of the Sternritter that included Giselle, and translator BadKarma confirmed that her text was saying she was, in fact, male.