Cyclades is (was) a packet-switching network developed in 1972 that had many of the attributes of a modern computer network. Cyclades was developed in France based on ARPANET after a group of French delegates were introduced to the technology on a visit to the United States. Cyclades introduced a number of new concepts that had a major technical influence on the development of the Internet.
Techopedia explains Cyclades
Cyclades was the first network to use datagrams and make network hosts responsible for delivering data, rather than the network itself. This was highly influential in the development of TCP/IP, which eventually became the language of the Internet. Cyclades also had a layered architecture, with a data transmission layer, transport layer and application layer.
Despite Cyclades' major strides in networking technology, it is still considered a footnote in the development of the Internet compared to ARPANET. This is because the European postal and telecommunications authorities chose to adopt the X.25 standard rather than packet switching as their data transmission protocol. As a result, they campaigned against packet switching networks and the use of the datagram. This eventually led to a reduction in funding for the Cyclades project, which led to its eventual dissolution.