- The user’s consent, or
- The cookie must be strictly necessary in order to provide the service explicitly requested by the user (Strictly Necessary Cookies).
The category of Strictly Necessary Cookies was previously interpreted rather narrowly. There must be a clear link between the strict necessity of the cookie and the delivery of the service. It is not sufficient that the cookie is merely necessary from an economic perspective to run a website. The Article 29 Working Party in WP194 regarded shopping cart, user authentication, security, load balancing, or multimedia player as use cases for Strictly Necessary Cookies.
The legal basis for so-called Reach Measurement Cookies has been heavily debated. Reach Measurement Cookies are statistical audience measurement tools for websites used to estimate the number of unique users, track the users’ interaction with the website and track down navigation issues. Typically, they have not been regarded as Strictly Necessary Cookies because websites can be provided to the users without measuring the users’ interactions with the websites. At the same time, Reach Measurement Cookies only provide useful findings if every users’ interactions with the websites are tracked.
In this context, the French data protection authority (CNIL) has provided guidelines (Guidelines) under which the Reach Measurement Cookies may be considered as Strictly Necessary Cookies and thus benefit from the consent exemption.