The last phase of the Bronze Age is represented by square enclosures with rounded corners surrounding a central cremation tomb. The succession of funerary enclosures, one built on another, makes it possible to observe their chronological development. The largest of the rectangular enclosures is more than 70 metres long and 12 metres wide. These are genuine sacred sites. The ditch was bordered on the outside by an embankment made from the chalk dug out of it, sometimes topped by a palisade. A large building 20 metres long and 5 metres wide was built to the east and a small hut on four posts occupied the western end. If there were tombs here, they have disappeared. A few shards have been placed symbolically in the ditch on either side of the entrance.
Some jars from western central France have engraved friezes probably depicting processions and religious activities in held within these enclosures.
Simple and plain pottery finds with evidence of imposing monuments are characteristic of this large cultural group from the final Bronze Age, centred on the middle and lower Rhine. Acy-Romance was by no means isolated and large enclosures have been found at Château-Porcien, Barby and Thugny-Trugny.