From the latest France Insider,
"According to Insee, the French national statistics agency, there were 3.1 million empty homes in France last year, equivalent to 8.2% of the housing stock.
"That is an increase of 60% since 1990, when 1.9 million homes (7.2%) were empty.
“Most of the increase occurred between 2005 and 2017, an increase averaging 3.3% a year, since when the annual increase has dropped to 0.8%.”
Yes but lets blame 2nd home owners before doing anything about empty homes 
First define “empty home”.
I suspect the problem with second home owners is WHERE they own their second homes. If they bought the houses that the French don’t want to live in then perhaps they would be better liked. OTOH if they buy in popular places, pushing up the price for locals then, just as we see in parts of the UK, this causes resentment.
Not to judge anyone in particular.
We’ve just got back from Wales. I still remember houses owned by English being burned in the 70s. Our next door neighbours bought a cottage in north Wales last year and have since discovered there’s some strong anti-English sentiment locally, although since she’s American it seems less problematic.
I better keep hold of my Grandfathers birth certificate then, just in case 
Prejudice doesn’t seem to care about such things.
Down my way, there’s schemes to help young locals find housing in the area.
The French inheritance laws are a real problem as if the surviving siblings can’t agree on what to do with their deceased parents property, it’s often a case on the last one standing deciding the property’s fate after decades of it sitting empty and neglected.
My old commune has slapped an “empty property” tax on such buildings now to free them up for local people to buy if the owners come forward and decide to sell and the commune has decided not to purchase them, which they did for several in the very centre of the village previously but for peanuts. So many were left to go to rack and ruin or just never visited from one year to the next.
Yes, there is a very nice house in the other side of the woods from us which has not been lived in for years, but every year the whole extended family descend upon it, with cars sporting reg. plates from 3 diifferent Departementes and spruce it up over a week or so. One year they even had a very posh swimming pool insxtalled.
My young German friend bought a house by sealed bid auction a couple of years ago from his Commune. Apparently it had lapsed to them because of donation from inheritors not interested. He won the bid and is doing a long reconditioning but had to wait after winning it in case the local farmers wanted to buy it at the price he bid. They weren’t required to make an increased bid.
there is another aspect… property which has been passed-down through the generations… is not necessarily easy to part with…
Some years back, I met a young man (30s) at the War Memorial… and we got chatting.
He was deeply distressed because he had just sold the family homestead…
“I am letting them all down… my father, my grandfather… his father and way, way back through the generations … they’ve worked and lived there and now it’s all over.”
Seems he worked across the other side of France and was the last survivor… trying unsuccessfully to keep this family property in decent condition to hand on to his children … as and when the time came.
His distress was very moving…
and he placed a plant at the foot of the memorial and said his goodbyes to the members of his family whose names were marked thereon.