Abstract: The invention relates to a method and a system for inserting thematic filtering information pertaining to objects accessible on an INTERNET site hosted by a server (SEj) by a client facility (PCi) The access request (Req) is intercepted (A) so as to store at least one transaction parameter pertaining to this request, this request is transferred (B) to the server (SEj) and upon response (Rep) containing at least one object of this site, the response (Rep) is intercepted (C) and at least one information-carrying computer object is selected from at least one object, a thematic analysis is performed (D) so as to produce a set of parameters (PT) characteristic of the site, coded categorization information IC (PT) is inserted (E) into the header of the response from the WEB server and/or the object itself, the response containing the categorization information is transferred (F) to the client facility (PCi).