Aside from the banking tip above, I am not sure I have any other tips for avoiding stress on arrival in France aside from simply "don't go".

As a same-sex couple who aren't married we also have some challenges most couples won't face. France, like the USA, does not recognise civil unions or anything other than a marriage when it comes to immigration. You're either married or single in their view. While for the USA, I remember we simply could not migrate there as a couple, the French at least acknowledged our situation and said I could have a visitor's visa and then get married once settled there with my visitor visa validated to become a residence permit (duration: 1 year).

The catch with the visitor visa however is that I had to fund my own health insurance (I found some expat insurance with Allianz which the French consulate said was acceptable) and also had to swear in a written statement that I would not seek gainful employment in France. It's hardly ideal.

My partner is a scientist, and because he was offered a research position at Lyon's university, he was given an expedited residence permit process. He went to OFII (immigration office) to confirm his residence permit about 3 weeks upon arrival in the country, and was exempted from all medical checks. His health insurance was provided using the French social security system. That last part took a while, but otherwise for him it was smooth as butter. I don't see why France couldn't apply this system to promising tech talent from abroad.

Now, for me the immigration process on arrival meant waiting 3 months for a letter from OFII for an appointment, which I couldn't make. That meant another 3 month wait, followed by medical checks including an X-ray, a talking-down-to by some immigration officials surprised that I hadn't learnt much of the language, and then a stamp on my visa. Now both residents, we could have applied for marriage at this stage, but we actually left for Germany just 2 weeks later - in France there is a one month cool-down period between marriage application and ceremony, so the timing wasn't possible. In any case, I would rather have a real wedding back home when it's finally legalised, rather than over here in Europe. No-one could really come...

Before I discovered Compte Nickel we had a hell of a time trying to get a bank account. We had an "attestation" from the university's housing board that we had an apartment reserved for us, but the bank first told us it was older than 3 months so no longer valid. Upon getting a new one the bank then said an attestation wasn't good enough anyway and we needed a rental contract to open an account.

We were staying in an AirBnB for our first month in Lyon and while the first two weeks looking around were pleasant enough, trying to organise long term accommodation and a way to get paid was super stressful. The university accommodation ended up being woefully inadequate so we cancelled that before we set foot in the place. Thanks to Compte Nickel and my partner's willingness to just pay a real estate company to find us an apartment, we got things sorted with mere days to spare before the AirBnB time was up, and things would have really gone haywire.

In France we made friends with a Finnish couple, an American couple, and a Finnish/French couple. 2/3 were also academics, and as married couples would have had much smoother immigration processes than ours. Despite this, all three planned to leave shortly after we did. None of us really liked it there. Lyon's suburbs are particularly filthy but even if I was in a smaller, prettier town I can't imagine being able to last very long.