Lambert has twenty years of experience in the arts and antiques market. He worked at Christie's in Amsterdam as cataloguer in the Impressionists and Modernists department. In mid-2016, Lambert joined Art Valuations as project coördinator and general valuer with broad knowledge of various disciplines. Since mid-2023 Lambert has been the owner of the appraisal agency.
Lambert is a recognized registered appraiser, member of the Stichting VRT, the Dutch foundation of united registered valuers, and candidate member of the Federatie TMV, the Dutch federation of valuers, brokers and auctioneers in movable property.