Investing in Sweden

Is the Swedish economy open to foreign investment? Do local authorities encourage investment (through formalities, tax etc.)?

Yes it is and they do help for instance this site was specially created for the purpose https://www.verksamt.se/en/web/international

What are the promising sectors to invest and do business in Sweden?

Hard to know but whatever it is, it has to be very big to earn money from it, since the labor market in Sweden is well paid with high minimum wages bargained by unions. And social security contribution of approx 32% on top of it and 25 days paid vacation and to pay for the first 14 sick leave days and also other local benefits such as uniforms/staff rums/Coffee/Christmas party etc.

Who do you turn to for information before investing your money? (organisation, professional, lawyer, consultant)
All needed informations in the website above, if not you always can contact them then they will guide you ahead.

According to the sectors of activity and the projects, what budget should be foreseen for an investment in Sweden?

Again it has to be big unless the company is a one-person company. And there are also different regulations for minimum own funds in the bank to get permissions to start different companies for instance to get the permission to start a taxi firm you need to show that you have 100000 SEK in your company account for the first taxi and 50000 SEK for the next one and so on. (note that there are other demands too this is only about financial demands)   

What do you think are the pitfalls to avoid and what advice would you give someone who wants to invest?

It's not worth to start small companies with few employees. In fact employees are the highest cost in Sweden. That is why many big companies shift their factories from here to other countries where the labor market is cheap. But if you have for instance a big number of employees then the government do everything to keep you not loosing because of employees but still there is no guarantee. You know what happened to SAAB car factory i.a

Buying properties and become a landlord is a good investment but to do that in some places in the heart of a big city like Stockholm you have to bid against oil princes if you ever be able to.

It's actually "staff rooms" NOT "staff rums". Not the alcohol. English room= Swedish rum. My bad!