LONDON/NEW YORK/FRANKFURT (Reuters) – Investment bank Lazard is working with Sanofi’s management to prepare a sale or listing of its Merial animal health unit, aiming to land the leading advisory job for the deal, which could value the business at up 12 billion euros ($12.7 billion), sources familiar with the matter said. Lazard is expected to win the role for the so-called dual-track process having helped Sanofi’s management in the ongoing review, the sources said, speaking on condition of anonymity. Sanofi and Lazard declined to comment.