PARIS, France — Alexander Mattiussi's interest as a designer is focused on product, more than image-making: he endlessly works on rethought staples that can be mixed in different ways and exude a quintessentially Parisian nonchalance. The satin trenchcoats, checked suits and printed k-ways he presented yesterday looked like Sunday best leisurewear: normal, but somehow special. Nothing to move the fashion horizon forward, but nice.