Interesting question, as it is a regular debate with the US/FR startup ecosystem.

Hiring is longer than harder: I already knew and contacted directly some of the engineers I wanted to hire. I also used GitHub and requested candidates to apply through a Pull Request (https://github.com/Dijiwan/Jobs).

I am not based in the US, and if I had to hire people there, I do not have enough step back to judge if I could have successfully operated the same way I did.

Most of all, the engineers hiring process was rather 1) an individual trust, 2) a cultural fit (we share the same values) than a "I want the most expensive guy on Earth". I value the individuality of people equally to their skills.
I think this is harder to achieve in a more money-driven environment.
Not being located in Paris but rather in a chilled out city like Bordeaux created an emphasis on the "we want to work and enjoy a good work/life balance". Working on the grass, at the coffee or a nap on the river bank while being able to have a 100% JavaScript codebase when it is your favourite language, this has no money equivalence ;-)

We had more problems with other roles, but I assume it is because we were not clear enough on the expectations and for the reasons explained in the blog post.

Hiring is a lot of paperwork. Firing is a lot of paperwork.
Jobs are sacralised in France and this is normal from an historical point of view: people fought for that. A lifetime full time job was the Nirvana of the Industrial Revolution.

Hiring someone should be a huge responsibility is most businesses: you not only deal with money but with individual's life. So you need to make sure you generate enough revenues to hire someone. It is an ethical debate, and cultural. I do respect individuals, whatever role they have in the company, and I want them to be able to be happy at doing it, even if it is not their dream job.

What was stupid on the business plan is the "hirings objective". They preferred us to hire 8 average engineers rather than 4 excellent ones. At a bootstrapping stage, I bet on reliability and efficiency. It is easier to scale conversations with 4 people rather than with 8.

What I think is wrong in the french public investment is they care too much about job figures and not enough about the company sustainability. Whereas I think in the US, investors care too much about the money and probably not enough about people (this is how I perceive it through the Internet lens, so certainly there is a bias in my opinion).
CEO are still perceived as bank robbers and slave masters. We like national companies to succeed but we hate so much people earning money. Maybe because there is an unfair wages balance between "high value" profiles and other people.

I wish it could be easier to be trained at creating companies, to be promoted and to be educated at creating a successful business. For this, I think US are way better than us. To market and to define a product as well, the US are far better than us.

We did not more money: we needed to make more money. We might have needed more money in the US, simply to scale with the salaries expectations (and to provide benefits, which are provided by the government here in France through the tax payer system; it linearise the cost over the entire country rather than creating an auction system for equal benefits coverage).

The failure we had was human: wrong persons at the wrong place making wrong decisions (including myself, except I think I did my leading job well; the cofounder one has been my weakness).
The failure we had was a product design: we had a super powerful tool and we did not know how to sell it, and we had the wrong persons to sell it.

We were pretty lucky (and probably worth it) to get that much funding. It took us one year (a year you have to fund on your own because you need to pay your bills meanwhile) to get it anyway. And investors have been fooled by some of the founders as we did.

So no, I do not believe the french system helped: we had access to free legal support.
The only lie we discovered is a continuing contract in France does not protect that much when your employer is not able to pay you. In that case, you are prisoner of a system rather than protected by it. This is wrong.

I do not know if it provides all the details you expected to have, so feel free to question me more about that :-)