The certificate of authenticity: drafting, securing and building trust

01The legal framework: what the law actually requires

In France, Decree No. 81-255 of 18 March 1981, concerning the prevention of fraud in art and collectibles transactions, requires the professional seller to issue an invoice or certificate bearing precise information: the artist's name, technique, dimensions, condition and, where applicable, provenance. The absence of these details can expose the dealer to liability in the event of a subsequent dispute.

The 1995 UNIDROIT Convention on stolen or illegally exported cultural objects reinforces the importance of documentary traceability. A dealer who provides a detailed certificate, accompanied by as complete a provenance history as possible, guards against potential ownership claims. Major galleries such as David Zwirner and Hauser & Wirth have integrated this requirement into their standard procedures: every sale is accompanied by a full documentary file.

Common law jurisdictions impose similar, sometimes stricter, obligations. In the United Kingdom, the Sale of Goods Act and the guidelines of the Society of London Art Dealers govern the authenticity guarantees that the dealer must provide to the buyer.

02Essential content

A complete certificate of authenticity includes at minimum the following: the artist's full name, year of birth and, where applicable, death, the title of the work, date of execution, technique and materials used, exact dimensions (height by width, and depth where relevant), the gallery's inventory number, a description of the signature (recto, verso, location), and, for editions, the impression number out of the total run (for example 3/8 or AP II/IV).

Beyond these mandatory details, the astute dealer adds information that enriches the document: the work's exhibition history, publications in which it has been reproduced, previous collections in which it has figured, and any pertinent technical notes (paper type for a photographic print, foundry for a bronze, weaving studio for a tapestry).

Galerie Perrotin, for example, issues certificates that function as genuine identity cards for the work, incorporating a high-resolution photograph, bibliographic references and exhibition history. This level of detail, which demands considerable documentation work, has become a standard expected by informed collectors.

03Who signs: artist, gallery or expert

The question of signature determines the document's evidential weight. A certificate signed by the artist offers the most direct guarantee. Most primary galleries, when selling works by living artists they represent, obtain the artist's signature on the certificate. Galerie Lelong & Co, Galerie Chantal Crousel and Galerie Nathalie Obadia follow this practice systematically.

When the artist is deceased, the certificate may be issued by a rights holder (heir, foundation), an authentication committee or a recognised expert. The Calder, Giacometti and Warhol foundations, for instance, served for years as the definitive authentication authorities for their respective artists' work. The dissolution of the Warhol Foundation Authentication Board in 2011, after years of litigation, highlighted the legal risks facing any entity that issues certificates for a deceased artist.

A certificate issued by the gallery alone, without countersignature from the artist or an expert, carries lower evidential weight. It nonetheless constitutes a useful document when accompanied by tangible evidence: correspondence with the artist, studio photographs, receipts of direct acquisition. Galerie Buchholz in Cologne and Berlin is known for the rigour of its internal documentation, which compensates for the absence of a formal certificate for certain historical pieces.

04Securing against counterfeiting

Counterfeit certificates of authenticity exist and represent a real risk for the market. Forged certificates were used to sell fakes in high-profile cases, most notably the Knoedler Gallery scandal in New York, where works falsely attributed to Rothko, Pollock and De Kooning were sold for years with fabricated certificates.

Physical security measures include watermarked paper, embossing, thermochromic ink and holograms. Some galleries use distinctive dry stamps that are difficult to reproduce. Sequential numbering of certificates, with a corresponding register maintained by the gallery, allows verification of a document's authenticity when doubt arises.

Digital solutions are developing rapidly. Services such as Artory and Verisart offer digital registries secured by blockchain technology, where each certificate is timestamped and tamper-proof. König Galerie was among the first to adopt this type of solution to certify its artists' works. Without necessarily adopting blockchain, a dealer can at minimum maintain a secure digital register of all certificates issued, with copies of photographs of each work.

05Certificates for editions and multiples

Editioned works — photographic prints, etchings, bronzes, screenprints — require an especially precise certificate because the medium's reproducibility makes authentication more complex. The certificate must state the total edition size (number of numbered copies, number of artist's proofs, number of hors commerce copies), the number of the copy sold, the printer or foundry, and the technical specifications of the printing.

For prints, the International Fine Print Dealers Association (IFPDA) has established documentation standards that specialist galleries observe. Galerie Lelong & Co, active in publishing prints for artists such as David Hockney and Sean Scully, issues certificates that follow these recommendations and serve as benchmark documents on the secondary market.

The dealer must also ensure the destruction of the matrix (printing plate, negative, mould) or its sequestration after the edition is complete, and note this on the certificate. This guarantee is essential for preserving the edition's value and protecting collectors' interests.

06The certificate as a sales tool

Beyond its legal function, the certificate of authenticity is a sales instrument. A hesitant collector is often reassured by the presentation of a professional, well-designed document that materialises the legitimacy of the transaction. The certificate embodies the gallery's seriousness and the permanence of its commitment.

Some galleries go so far as to make the certificate an object in itself. Galerie Templon presents its certificates in branded card folders with polished graphic design. White Cube in London uses a standardised format, instantly recognisable, that has become a hallmark of quality on the secondary market. A collector reselling a work accompanied by a White Cube certificate benefits from additional buyer confidence.

It is in the dealer's interest to deliver the certificate within days of the sale, accompanied by the invoice and conservation recommendations. Delaying delivery creates an impression of negligence and can prompt unwarranted concern in the collector.

07When the certificate is missing

In the trade of historical works or on the secondary market, the absence of a certificate is common. The dealer then finds themselves in a delicate position: selling a work without a certificate carries risks, but refusing an authentic work for want of paperwork would be excessive.

The solution lies in assembling a substitute dossier: archival photographs showing the work in an exhibition or collection, mentions in catalogues or publications, correspondence with the artist or their circle, and a written opinion from a recognised specialist. Marian Goodman Gallery and Gagosian employ research teams capable of reconstructing complex provenances for major works that have passed through multiple collections.

For living artists, the process is simpler: contact the artist or their studio to obtain confirmation of authenticity. Most artists maintain photographic archives of their works and are able to confirm or deny the authenticity of a piece. The dealer who undertakes this process on behalf of their client provides a considerable service and strengthens trust in the commercial relationship.