Interfacing organza would be my guess.
If you are into making couture-esque clothing, the I have a book tipp:
https://www.amazon.de/-/en/Kenneth-D-King/dp/1589233891/ref=sr_1_12?crid=WW87SSKL5G7H&keywords=k%C3%B6nig+kenneth&qid=1653673627&sprefix=king+kenneth%2Caps%2C73&sr=8-12