HAL-ENS Open Archive — ENS-PARIS collection
ENS research output is deposited into the ENS-PARIS collection of HAL, the French national open archive operated by CCSD (CNRS). The collection is real and substantial — HAL's ENS-scoped Search API returns 84,784 records — and it is harvestable as the OAI-PMH set collection:ENS-PARIS. The data and the curation are ENS's; the platform, the protocol endpoints and the API contract are CCSD's, so nothing is stored under this institution and the surface is recorded as a tenant relationship rather than an ENS API. The ENS portal front end at hal-ens.archives-ouvertes.fr is live but serves a bot challenge to automated clients.