The amfAR gala in Cannes is the place where Hollywood and high fashion check into the same hotel on the same night - and where every gown is the result of seven hours of prep and a three-year plan from some design atelier. This year the scene was classic: more feathers than necessary, more gold mosaics than recommended, and a parade of stars from three different eras of beauty.

Eva Longoria wore an Oscar-worthy strapless gown with a beaded mosaic and voluminous hair - choreography on the beat of "look at me, but not too loud." Classic Eva, with much more fabric than necessary, but with real restraint in movement.

Bar Refaeli went with a Stella McCartney gown in lavender - tight, asymmetrical, with a ruffle at the edge. Not the strongest choice for her tone, but Stella McCartney is a designer that sells on name recognition, not on individualised fit. That determines the outcome.

Natasha Poly chose the minimalist route - a white blouse and a maxi skirt. When you're a supermodel and you need the least amount of effort to look in shape, that's the move. The rest of the guests had the rule of "the more the better." Poly doesn't think that way.

Isabel Goulart wore a Giorgio Armani Privé gown in black with sequins - classic Armani, no surprises, with a lot of control over the form. That's a style that doesn't age; a style that will be worn from 1995 to 2050 without anyone noticing it's old.

Leonie Hanne and Coco Rocha took the theatrical options - feathers, architectural volumes, tall elements. That's what's expected of fashion influencers at a gala - to look like photographs, not like women. The two did it without hesitation.

What does all of this tell us? Nothing. The gala sells itself as "a humanitarian evening," but the reality is that every 30,000-euro gown is an auction for the press. amfAR raises money for HIV research - that's a real and important cause. But the path from the red carpet to the lab is longer than Instagram tells you. And that isn't bad, that's just the truth.