The unveiling marked the 111th anniversary of his death on Wednesday.
Everett, who is writing about the poet's life, spoke at the ceremony as he held up a poster of the pre renovation tomb covered in notes and lipstick at Paris' famed Pere Lachaise cemetery.
The tomb had become such a well-loved pilgrimage site - and had been so well-kissed - that it needed renovation. A glass screen now separates visitors from the stone itself.
Everett hailed Wilde's "force" and the "amazing trajectory of his life."
Grandson Merlin Holland said his grandfather "would be incredibly touched by all the attention. After all he was sent out of England in 1897 a bankrupt, a homosexual and a convict ... and the French took him to their hearts."
The Associated Press contributed to this report.