This film is 50 years old this year and you have to accept that it's dated and directed by a Frenchman. However, the 20-something Jane Fonda is a feast for the eyes and worth the rental at twice the price. I believe the correct term to be applied is "Phwoar."
The plot is nonsense but the acting performances are sublime. To work this sort of thing needs to be performed dead-pan and it is, there are no duff characters. It's actually very funny in places. Plus you get to know where the band Duran Duran got their name from.
It's unashamedly sexist but that's the way things were then - I've seen much worse, there's no horrible humiliation. The erotic costumes wouldn't make it into mainstream cinema, though. I watched it with my 20 y.o. son and his eyes were out on stalks. The routine awfulness of the internet completely lacks the irony, humour and gentle eroticism of Barbarella. In its unique way it's a bit of a masterpiece.
You may want to see this for the wacky comedy element, but don't expect to take it seriously - unless you are able to toatally suspend all rational thought! Incredibly 60's. & if you are expecting anything erotic, I didn't notice it. However, you may want to see it as an interestic piece of the history of film-making.