Hello Jean François,
On the advice of the moderator, I will provide a detailed response. 
Your comment initially annoyed me
, but now I am simply perplexed. However, my love of hiking and my desire to share it with others outweigh my initial reactions... 
You have been a Visorandonneur since 22 July. That's great, we should welcome newcomers and encourage them to continue. However, your judgement of someone who has been here longer seems a little harsh. You haven't posted anything yet, this is your first comment and you are publicly attacking someone...
A little patience and encouragement for those who take the trouble to publish their routes wouldn't hurt!
I've done this "hike" about fifteen times and everything described is perfectly accurate.
The route couldn't be simpler or shorter. Anyone can follow it on the IGN map and even on Google Maps. To question its reliability is surely to admit that you got lost... I'm willing to accept partial responsibility for that, but please be more specific about where you went wrong on the WP...
Regarding your warnings about the risks involved, a number of alerts are already included in the "Practical information" section. I'm not opposed to adding more if the moderators deem it necessary...
I will respond to your arguments in detail:
This hike crosses his property at two points. This is incorrect. It follows the concrete canal embankment and then the canal bridge, which is the exclusive property of ERDF and is not fenced off, but it does not belong to the farmer. Furthermore, the farmer does not own his plots of land but only rents them from the city. The hike does not pass through "his" plots.
We spoke with the farmer, who explained his disagreement with this route, which I understand: ... with his herd guarded by patous that are not inclined to let "strangers" in, plus the crossing of the orchard, which appears to be subject to some illegal harvesting.
This hike does not cross his fields, land, yard, etc., where his goats and patous are kept, nor his orchard, but only a path running alongside his orchard, which is part of the public domain of the municipality of Villefranche. Either you are mistaken, or the farmer is spreading misinformation or acting in bad faith.
The orchard is next to the D6, with a small path that is convenient for parking, and it is more likely that you will find the thieves there than among the hikers or runners.
If the trail does indeed pass close to his fields, in an unfenced area alongside the canal leading to the nearby hydroelectric plant, it causes no inconvenience other than ill-placed irritability.
However, I am mentioning it in the description, as the farmer does not appreciate people passing close to his property, so I would reiterate my recommendation to pass slowly and quietly so as not to upset the animals or their owner...
In addition, the descent to the fish ladder is overgrown,
Agreed... It is a path in the undergrowth, but passable by any hiker, including 5-year-old children if necessary. It is not a GR (long-distance footpath), of course, otherwise I would have mentioned it... 
crossing the dyke for more than 300 m (which is private property belonging to the hydroelectric company) is clearly prohibited by signs
Exactly. Hence my comment. "This risk seems far greater than the risk of walking or running along the N116." Now, everyone must take responsibility for their own actions in full knowledge of the facts. No one forced you, JF, to take the canal when you saw the prohibition signs! The same goes for all other hikers.
and is dangerous in damp undergrowth (vipers coiled around the handrails).
That's right, nature is full of horrible and dangerous animals that put hikers' lives at risk...! Yes, JF, on this canal as everywhere else in France... But personally, I have never seen a single viper (or any other snake) on this route. 
I think this route should be removed from the website. I obviously don't share this opinion... Dozens of people travel to Villefranche regularly by road. Suggesting an alternative route to the RN is a lifesaver! 
I would add that the route could avoid the canal if the farmer hadn't closed off the end of the path that continues after WP(1).
On the land registry, the communal path arrives just after the farmyard and allows you to safely rejoin the last section of the D6 road via a bridge crossing the Rotja. But he is not complying...
Let everyone choose their side in full knowledge of the facts.
Don't impose too many restrictions, there are already enough as it is...
I hope I haven't offended anyone!
Enjoy your walks in our beautiful Pyrenees!
Best regards
Machine-translated