Calling Sampaio the "glam standard-bearer of a cause that is on the march", the French edition of Vogue describes the 22-year-old as a "femme fatale" who happened to be born a boy.
"Beyond her evident physical qualities and her sparkling personality, (Sampaio) embodies... a long and painful fight against being perceived as a 'gender exile'," Emmanuelle Alt, the magazine's editor-in-chief, writes in her editor's letter.
A sultry Sampaio, bathed in dark purple and blue light, appears over the words "Transgender Beauty", with a subtitle reading "How they are shaking up the world," on the cover to appear on newsstands February 23.
Transgender people are increasingly emerging from the shadows.
Caitlyn Jenner, a former male US decathlon star, made history by coming out with the June 2015 cover of Vanity Fair, prompting Glamour US magazine to name her woman of the year.
"Vogue supports and chooses to celebrate" transgender people "in a post-gender world," Alt writes.
She pays homage to other transgender figures who have preceded Sampaio and Jenner such as Lea T, the muse of Givenchy designer Riccardo Tisci.
She also recalls the trauma endured by supermodel Caroline Cossey, who was an extra in the 1981 film "For Your Eyes Only" and posed for Playboy that year before being outed by Britain's now-defunct News of the World tabloid in 1982.
In December, the US magazine National Geographic's cover story was titled "Gender Revolution" and featured Avery Jackson, a nine-year-old transgender girl.
Laverne Cox, who stars in the TV series "Orange Is the New Black", was on the cover of Time magazine in June 2014.
Cosmetics group L'Oreal Paris has selected 24-year-old transgender model and actress Hari Nef to represent its latest foundation cream in a global ad campaign.
Alt writes: "The day when a transsexual poses for a magazine cover and it will be no longer necessary to write an editorial on the subject, we will know that the fight has been won."