In Paris, an empty Art Deco postal office is on its way to becoming Bank of America’s headquarters for its European brokerage arm. Where telegraph operators once tapped out messages, hundreds of traders and sales people will be working by spring. In Frankfurt, Morgan Stanley’s European hub will double its staff of 200. Germany’s financial center, which wooed financial firms in London with a “Fall in love with Frankfurt” video, is welcoming investment bankers from Goldman Sachs and Citigroup.