Since they showed up all other telcos in France had to adjust and offer around the same, around 25€ max instead of the usual 60€ to 80€ they'd offer before Free.
I also have a portable 4G hotspot with unlimited data (I've used around 50GB this month) for €4.90/mo, including rental of the device. It's limited at 6 Mbit but that's fine for my needs (you can pay more for up to 25 Mbit). However the main reason why it's so cheap is because it's from a smaller operator, so you only really get coverage in big cities and even then it can be patchy (like Three when they first launched in Europe).
Home internet is a different story though. I pay €9.90/mo for unlimited 100/100 FTTH, and I can get up to 1000/1000 for €19.90/mo - downloading a 6GB Steam game in under 10 minutes seems fast enough though. In 2015 home broadband coverage (>= 30 Mbit) was 99%, with 62% of subscribers on fibre [0].
They have several phone models to choose. You pay 1 EUR for most models from Samsung or Sony, a bit more for the deluxe editions (iphone and sorts). Now they even offer more because SMS are free and I still pay extra for each one, but doesn't matter because I simply use other messaging apps.
The Sony Xperia models are good, they're waterproof by default and resistant to shocks, albeit camera is crappy (compared to normal Samsung models)