CE Marking Rules: Affixing and Format Requirements

Article 23 establishes a strict sequencing requirement: the CE marking must only be affixed after the manufacturer has completed all applicable conformity assessment procedures. For default-class products, this means completing the Module A self-certification process, preparing the technical documentation under Annex VII, and drawing up the EU Declaration of Conformity. For Annex III products, the relevant notified body involvement must also be complete.

Affixing the CE marking before completing these steps — even if the manufacturer intends to complete them later — is a violation. The CE marking is a declaration that conformity has been achieved, not an aspiration or a work-in-progress indicator.

Manufacturers should build the conformity assessment process into their product launch timeline, treating it as a mandatory pre-launch gate rather than a parallel or post-launch activity.

Article 23 requires the CE marking to be visible, legible, and indelible. These three requirements have specific practical implications:

Visible: The CE marking must be placed in a position where it can be seen by the user without disassembly or special tools. On physical products, this typically means placement on the product casing, its packaging, or an accompanying label. For digital products, the marking must be accessible in a readily accessible location in the product's interface or documentation.

Legible: The marking must be clear and easy to read. The CE marking has a minimum height of 5mm under EU product regulation conventions. It must be printed or affixed with sufficient contrast against its background to be readable.

Indelible: The marking must not be easily removed or defaced during normal product use, transport, or storage. Adhesive labels that peel off easily may not satisfy the indelibility requirement for physical products — the marking should be engraved, moulded, printed, or otherwise permanently affixed.

Where the nature of the product makes it impossible to affix the CE marking on the product itself (for example, a software-only product distributed electronically, or a very small component), Article 23 allows the marking to appear on the packaging, on a label attached to the product, or in the accompanying documentation.

For purely digital software products, the CE marking can be included in the installation interface, the product's 'about' section, the product's user interface, or in documentation provided with the product. The key requirement is that it is accessible to the user and clearly associated with the product.

For products sold with multiple items (for example, a device with accessories and documentation), the CE marking must be visible on the primary product — placing it only on a box insert that users may discard is not sufficient.

Article 23 prohibits the affixing of any marking, sign, or inscription that could be confused with the CE marking or that could mislead users about the product's compliance status. This prohibition targets spurious markings designed to give the impression of compliance when none exists.

Specific examples of prohibited markings include imitations of the CE marking format (the two-letter stylised logo), claims of 'EU cybersecurity certified' without a formal certification process, or third-party security seals that imply regulatory compliance without a proper basis.

Manufacturers using legitimate third-party security certifications — such as Common Criteria, SOC 2, or sector-specific security labels — may display those certifications alongside the CE marking, but must ensure they are clearly distinguished from the CE marking and do not create confusion about the regulatory basis of compliance.

For Annex III products where a notified body has been involved in the conformity assessment, the notified body's identification number must appear alongside the CE marking. The number must be in the same field of vision as the CE marking and must be visible without any disassembly.

The notified body number is a four-digit identifier assigned to the body at the time of its notification and listed in the NANDO database. Including this number signals to market surveillance authorities and users that a third-party assessment was conducted, enabling them to identify the assessing body and retrieve the assessment records.

For default-class products (no notified body involvement), the CE marking appears alone without any notified body number — the absence of a number is not an error but rather the correct presentation for self-certified products.