From Amazon because they can do it better than me :
Young, attractive and very ambitious, George Duroy, known to his admirers as Bel-Ami, is offered a job as a journalist on La Vie francaise and soon makes a great success of his new career. But he also comes face to face with the realities of the corrupt society in which he lives - the sleazy colleagues, the manipulative mistresses and wily financiers - and swiftly learns to become an arch-seducer, blackmailer and social climber in a world where love is only a means to an end. Written when Maupassant was at the height of his powers, Bel-Ami is a novel of great frankness and cynicism, but it is also infused with the sheer joy of life - depicting the scenes and characters of Paris in the belle epoque with wit, sensitivity and humanity.
I didn't like this as much as his other work but it was well written, well plotted and had believable characters.