Frankish clothing refers to the style of clothing worn by the Frankish or merovingian peoples, living in France c600-800AD. Basically a t-tunic, but worn with distinctive length, decoration and accessorising.
The basic outfit for the Franks depended on class and rank. The peasants wore "a hooded headdress, a shirt of rude linen, and a loose garment. He wrapped his legs in narrow strips of cloth and shod himself with heavy shoes" (Riche 161)
The wealthier classes however, wore finer clothing. The Frankish ruler, Charlemagne is described by his biographer Einhard, as usually wearing a shirt and linen drawers covered by an embroidered silk tunic and trousers. This was covered by a vest of otter or rat skin and a great mantle. He also wore leggings around his legs and feet (Riche 162) While not all the nobles would follow Charlemagne's fashion exactly, it is more than likely they were clothed similarly.
In a different style than men, women wore their clothing to appear tighter. They would wear a great mantle over a large-sleeved tunic. The tunic would be tightened by a heavy, jeweled belt. It seems jewelry was very common for the Frankish women. Riche goes on to explain that the women would wear jeweled headdresses over their veils and bedeck themselves in all manner of jewelry, such as rings, necklaces, bracelets, broaches, etc. (Rich 163)
What must be kept in mind, is the above descriptions refer to the Frankish people and clothing around the time of Charlemagne, so mainly from the late 8th century to the early 9th century.
Sources: Riche, Pierre, Daily Life in the World of Charlemagne, University of Pennsylvania Press, 1978