Complex sentence: Breguet did not staff his workshops in the traditional way, with unskilled apprentices, but instead sought out the finest available watchmakers in Paris, whom he employed to make watches to his own designs.
Split into simpler sentences: Breguet did not man his workshops in the traditional way, with unskilled apprentices. Instead, he sought out the finest available craftsmen in Paris, who he employed to make watches to his own designs.