In March 2016, two pilgrims walked the Napoleon route although it was already prohibited at the time but this legal prohibition was less well known than now. One of them fell and got injured and immobilised and it was night time. It had snowed and at higher altitude there was a lot of snow on the ground. She managed to get in touch with the rescue services - it was also more complicated then than now - and luckily she was rescued by helicopter. This is the mother of all the stories about fines.
At the time, the decree of the regional government about the closure of the Route Napoleon during the winter period November to March mentioned two things: first, a list of the charges for a rescue operation, i.e. man-hours, terrestrial vehicle, helicopter and so on. There may or may not have been mention of a fine in addition to these operational charges - I would have to look up the wording of the 2015 decree to be sure.
Later decrees and the current decree do not list any charges for a rescue operation. I would have to look up the wording to know whether there are any fines mentioned. If so, it is not a sum, whether €120 or €12.000, but rather a vague reference to a different and more general law.
I don't know for certain whether the pilgrims of March 2016 - there were two who are known to have walked on that day despite the legal closure of this part of the Napoleon trail on Spanish territory but they were separate - were charged for the rescue in the end or even fined in addition to the operational charges.
The first responder team - Bomberos - opposed even the charges, see this article:
Pide que se paralice la facturación del salvamento de dos peregrinos brasileños
www.noticiasdenavarra.com
Quote from this article (machine translation): In the case of the peregrina, as detailed by the Government of Navarre last week, € 5,360 were billed for the use of a rescue helicopter and for the 12 hours of work of 11 people, and in the case of the peregrino €450 corresponding to a three-hour operation carried out by 4 first responders and a terrestrial vehicle. These amounts do not include the health services provided or the use of the medical helicopter, which would also be billed by the Health department.