Kristin Scott Thomas has dropped out of the upcoming Paris production of “A Little Night Music” due to a foot injury, with Greta Scacchi stepping into the role of fading actress Desiree Armfeldt.Scheduled for Feb. 15-20 at the Theatre du Chatelet, the English- language staging of Stephen Sondheim and Hugh Wheeler’s 1973 waltz musical also stars Lambert Wilson as Fredrik Egerman and Leslie Caron as Madame Armfeldt. Lee Blakeley directs the production, which features the Philharmonic Orchestra of Radio France. French newspapers reported Thomas’ withdrawal from the production earlier this week. Scacchi has since been added to the cast list on the Chatelet website. A revival of “A Little Night Music” starring Catherine Zeta-Jones and Angela Lansbury opened this month on Broadway to strong business.