The butler : a novel / Danielle Steel.

Enhanced descriptions from Syndetics:

Two different worlds and two very different lives collide in Paris in this captivating novel by Danielle Steel.

Joachim von Hartmann was born and raised in Buenos Aires by his loving German mother, inseparable from his identical twin. When Joachim moves to Paris with his mother in his late teens, his twin stays behind and enters a dark world. Meanwhile, Joachim begins training to be a butler, fascinated by the precision and intense demands, and goes on to work in some of the grandest homes in England. His brother never reappears.

Olivia White has given ten years of her life to her magazine, which failed, taking all her dreams with it. A bequest from her mother allows her a year in Paris to reinvent herself. She needs help setting up a home in a charming Parisian apartment. It is then that her path and Joachim's cross.

Joachim takes a job working for Olivia as a lark and enjoys the whimsy of a different life for a few weeks, which turn to months as the unlikely employer and employee learn they enjoy working side by side. At the same time, Joachim discovers the family history he never knew: a criminal grandfather who died in prison, the wealthy father who abandoned him, and the dangerous criminal his twin has become. While Olivia struggles to put her life back together, Joachim's comes apart.

Stripped of their old roles, they strive to discover the truth about each other and themselves, first as employer and employee, then as friends. Their paths no longer sure, they are a man and woman who reach a place where the past doesn't matter and only what they are living now is true.