Julia Restoin-Roitfeld, the fashionable daughter of former French Vogue editor Carine Roitfeld, is about three months pregnant with her first child. Julia announced the news on Facebook to her friends yesterday, calling herself a “future mommy” and posting photos of herself and her boyfriend and baby daddy, model Robert Konjic. Julia walked down the pink carpet at the Victoria’s Secret show Wednesday night in a black hip-hugging dress that showed only a hint of a baby bump. “They are a happy couple — so in love,” said a friend. Thursday night, Julia joined Carine for a showing of the short documentary “The Client,” starring Carine herself, at an event with W magazine. W editor in chief Stefano Tonchi asked Carine about becoming a grandmother, and she gamefully responded, “I will be called ‘Madame.’ ” Also at the screening were Olivier Theyskens, Haider Ackermann, China Chow, Prabal Gurung, Patrick Demarchelier, Rachel Roy and Doutzen Kroes.