An avid film fan from childhood, Warren entered the film industry as a runner on The Millionairess (1960) and as an assistant director (The Dock Brief, 1962) before directing the short film Fragment in 1965.
Asquith chose Sophia Loren for Andros's role, remembering the box-office success of the romantic comedy film The Millionairess (1960) he did with Loren in the main role.
He did some work on Broadway, wrote the screenplay for an adaptation of George Bernard Shaw's The Millionairess which Katharine Hepburn, who had performed in the play in New York, wanted to get produced, and then came to France where, because he was fluent in French, he was able to write and direct the screenplay for this adaptation of Pierre Daninos popular novel.