The present invention relates to a composite matrix that includes a reinforcing textile portion having two surfaces coated over at least 90% of the respective surface areas thereof, by means of at least a first layer including at least one resorbable macro-molecule and having a collagen content of between 50 and 100 wt % relative to the total weight of the first layer the invention also relates to a prosthesis including such a matrix and to a method for preparing said matrix.