In 1859, he visited London, where he met Lacy, who had given up the stage and been active as a theatrical bookseller since the mid-1840s.
Lacy, who had removed his shop from Wellington Street, Covent Garden to 89 Strand in 1857, had also started publishing acting editions of dramas.
Lacy's Acting Edition of Plays, published between 1848 and 1873, would eventually run to 99 volumes containing 1,485 individual pieces.
Lacy died in the same year, and French finally established his name as the most important theatrical publisher in England.
At the time of his own death in 1898, almost all renowned English playwrights of the present and recent past had been represented by his company.