A shielded subminiature connection assembly having two subminiature connectors with housings provided with means of locking, two molded thermoplastic half-shells having a high contact density miniature sub-assembly with a molded thermoplastic insulating body provided with contact cavities for the positioning and retention of contacts, a back plate provided with a contact-retaining clip and whose sidewalls comprise projecting members, a molded thermoplastic receptacle shell including a flange provided with oblong apertures into which the projecting members of the back plate are locked. The disclosed embodiments also concern the process of forming the connection assembly.