Preventive excavation in the ancient Forum Iulii city (Fréjus, southern France) in 2013 revealed a housing block where a very well preserved charred wooden floor was discovered. It was laid in a house dating back to the first half of the 1st century AD and used as the floor of a room decorated with painted plaster. It was destroyed by fire around 70 AD. The ligneous species used for its construction (Aleppo pine, Scots pine, beech and fir) were characterized by anthracological analysis. Numerous traces of xylophagous insects and lignivorous fungi were observed. Their identification, their number and their distribution in the floor open on to very interesting new interpretations for both anthracologists and archaeologists as regards the condition of timber, the original source of the infestation, and the historical record of the building. This study is a direct and unprecedented application of a key for identifying traces of wood-boring insects in charred remains from the Roman period. Field samples were tested during the excavation of Camelin block, and microscope observation protocols were adapted to entomo-archaeology during anthraco-analysis.