Israel Horovitz is staying busy this summer. The celebrated playwright’s 1986 comedic drama, ”North Shore Fish,” opens at the Gloucester Stage Company Thursday. Alas, Horovitz, who cofounded the theater company in 1979, won’t be able to see the show because he’s in Paris. Perhaps even more relevant today than when it was written, “North Shore Fish” is about the challenges facing Cape Ann’s fishing industry — as explained, of course, by an entertaining group of Gloucester women in a fish processing plant. The new production is being directed by Robert Walsh, who previously directed Horovitz’s “The Widow’s Blind Date” and “Fighting Over Beverley.” So why is the playwright in Paris? He’s getting ready to direct the film version of his play “My Old Lady” — with an impressive cast. Two-time Academy Award-winner Maggie Smith, Kevin Kline, Jane Birkin, and Dominique Pinon are set to star in the film about a penniless New Yorker who inherits a beautiful Parisian apartment only to discover that it’s occupied by 94-year-old Mathilde, played by Smith, and her daughter Chloé, played by Birkin. Reached by e-mail in France, Horovitz sounds excited and perhaps a little intimidated about his directorial debut. “Hopefully, I’m not too much less than [Smith] deserves,” he said. “Maggie Smith, Kevin Kline, Jane Birkin — C’est pas mal, quoi?”