The team of archaeologists analysed 257 footprints discovered at Le Rozel on the coast of Normandy, northern France, and found that they belong to a group of between 10 and 14 individuals, most of whom were children including a two-year-old.
Judging from foot size, the few adults present were very tall - up to 190 cm (6'3").
It is thought the footprints were imprinted on muddy soil, then quickly preserved by sand blown by the wind when the area was part of a dune system, thus preserving them for tens of thousands of years.
The Rozel site was discovered by amateur archeologist Yves Roupin in the 1960s, but excavation work only began in 2012 amid fears of tidal and wind erosion.
Tens of metres of sand were extracted with mechanical shovels to reach the layers with the footprints.
Careful brushwork led to the identification of 257 footprints between 2012 and 2017, and hundreds more since. Each of the footprints was photographed and modelled in three dimensions and casts were taken of a few of them. Thanks to new chemical technique available to the team since 2017, hundreds of the prints were lifted from the site to be preserved elsewhere.
They were found among what the team called "abundant archeological material" indicating butchery operations and stone tool production. These date back to a time before Homo Sapiens lived in western Europe.
Before Rozel, only nine confirmed Neanderthal footprints had been found, in Greece, Romania, Gibraltar and France.
Jeremy Duveau, a doctoral student at France's National Museum of Natural History and one of the study's co-authors, said: “The conservation of footprints requires a sort of miracle: we have to get very, very lucky.”
"They record a kind of snapshot into the lives of individuals over a very short period,” he told AFP.
But he said there was no way of knowing whether the lack of adults was because they died young, were elsewhere or were not “outside at the time”.
As for the children, just like humans, Neanderthal kids may also have simply loved spending time at the beach.