Philippe Plein, a German fashion designer who a year ago offered his first high-end line of sports shoes and clothing, called Plein Sport, has signed up Floyd Mayweather, the 40-year-old American boxing champion. Plein announced the two-year contract shortly before Mayweather came out of a two-year retirement to win a highly publicized 10-round match against a 29-year-old Irish contender, Conor McGregor, on Aug. 26 in Las Vegas. A dedicated collection of garments has just been launched. Philipp Plein, whose company is based in Switzerland, has also become the gold sponsor of a local ice hockey club, HC Lugano.