France has a surface of 643,801 km², or 643 billion m². It is also assumed that you can be self-sufficient in vegetables with a plot of 200m² per person. In theory, France could feed a billion vegetarians. 3 billion if you wipe out every city to create one big garden.
Grain crops and animals occupy most of the agricultural land, so consuming these would significantly increase the space you'd need to be self-sufficient. Half of the global arable lands are used to grow grains, which represent about 14% of the worldwide agricultural surface and 5% of our landmass. Pigs, goats, and chickens don't take much room and can help at the garden though.
In other words, it's very likely we could eradicate hunger with the right political and individual decisions, whether in France or in the whole world. There are enough agricultural lands and food for everyone, we just aren't willing to share or help countries in need to reach food safety.
Lately, I've been interested in Fukuoka's work about transforming deserts into arable lands. Fukuoka is the author of The One-Straw Revolution, the Japanese farmer who started the whole permaculture movement. His work is absolutely fascinating. Even if half of your country is desertic, there is still hope.
And even if there is not enough land to feed everyone, which I highly doubt if governments leveraged their brightest minds, vertical farming could still be used.
When you read about people like Fukuoka or Yacouba Sawadogo in Burkina Faso, it's clear that money is not what's going to solve hunger—even if money can always help: it's about education and having the right persons in charge.