Nathalie,
As you might know, the current IPv6 policy states very clear that assignments to customers must be a minimum of a /64.
5.4.1. Assignment address space size
End Users are assigned an End Site assignment from their LIR or ISP. The size of the assignment is a local decision for the LIR or ISP to make, using a minimum value of a /64 (only one subnet is anticipated for the End Site).
https://www.ripe.net/publications/docs/ripe-655
On the other hand, a while ago, RFC7608 (BCP198) was published, stating:
2. Recommendation IPv6 implementations MUST conform to the rules specified in Section 5.1 of [RFC4632].
Decision-making processes for forwarding MUST NOT restrict the length of IPv6 prefixes by design. In particular, forwarding processes MUST be designed to process prefixes of any length up to /128, by increments of 1.
In practice, this means that the RFC suggests that a customer can get an IPv6 assignment of any size, while the RIPE policy says the minimum should be a /64. I’m interested to know what the community thinks about this and if alignment between this RFC and the RIPE policy is needed.
That is an interpretation of RFC7608 that I hope is not common. RFC7608 is written for the purpose of ensuring that forwarding engines (and routing protocols) are built so that they can handle any prefix length. Apparently some implementations treated IPv6 as classful, and only supported forwarding of prefix lengths from 0-64 and 128. RFC7608 has absolutely nothing to do with end-site address assignment. The IETF consensus on that is in RFC6177. Best regards, Ole