I was on the island in June 2018 and witnessed two squatters living in chalets behind Papagayo ruins. I reported it to an owner on the beach and warned him about squatters rights. French Law you can not forcibly remove squatters without a court order.

Only if you happen to have discovered their presence on the property within 48 hours of entry have you been entitled to call upon the assistance of the local police/gendarmes to secure their immediate removal from the property.

https://www.french-property.com/news/french_property/squatters_eviction/

In France there are new Laws but only for property if it is your principal residence, not your second home.

If it does not apply, then second home owners will continue to be required to obtain a court order, unless they are able to act within 48 hours.

It is a process that is long and expensive, requiring the use of a huissier as well as legal representation.