FATCA is a good example of the risks of international cooperation in regard of collecting taxes.
FATCA is the US legislation that obliges countries and financial institutions all over the world to provide the US tax authorities with personal financial data of people outside the US. In relation to FATCA the US has concluded a lot of treaties  and has threatened foreign financial institutions with sanctions in case of non-cooperation.
There is nothing wrong for a country in trying to collect tax. There are more treaties and other initiatives in relation to collecting tax and to let companies and people a fair share.
The problem of FATCA is that the US is not only imposing tax on people and entities that live/are in the US or that have voluntarily obtained the US nationality (as all other countries in the world do). As far as I know the US is the only country in the world that is having such a broad scope of people and legal entities that it is regulating .
The US Person and the accidental American
As I explained in an earlier post (in Dutch) the US imposes taxes on the so called ‘US Persons‘. The concept of US Person includes people that have no relation with the US. You can be a US Person when you are born in the US from non-US parents during a short stay, or when you are born outside the US and one of your parents has the US nationality . These people were often unaware that they were a ‘US Person’, that changed when FATCA came into force . They call themselves ‘accidental Americans‘ and are in a completely different position from the regular Americans.
By imposing rules on these accidental Americans, the US to my opinion acts against basic human rights principles.
US laws applicable in Europe?
There are more obligations for US Persons than the obligation to file tax returns and pay taxes in the US. Certain financial legislation is applied outside the US, in Europe having the consequence that European banks (who have the European legislation to comply with) do not want to provide financial services to US Persons. Even sanction law seems to apply to accidental Americans (read this). 
US Persons outside the US are having all sorts of practical problems, leading to articles like “Overseas Americans Can’t Open Foreign Accounts Because of FATCA? Court Says Tough Luck!” (5 May 2016).
In Europe the opposition against this extraterritorial working legislation is growing. In the European Parliament questions have been asked . I read FATCA will be discussed again.
In France the accidental Americans have started a procedure that ended unsuccessfully at France’s Conseil d’Etat that ruled in support of current FATCA regime. The ‘accidentals’ intend to bring the case before the Court of Justice of the European Union .
Human rights in financial law
FATCA shows the world-wide consequences of financial legislation that violates human rights. The position of the accidental Americans make me wonder if this is in accordance the human rights treaties and principles that apply in Europe .
As tax legislation in countries is changing all the time and may include anti-social elements (similar to the obligations of the accidental Americans in the US tax system), I think it is important to see if the current system of human rights adequately covers the international financial human rights every person is entitled to.
 A list of treaties can be found here. Wikipedia has a page.
 Something to be looked at further.
 Explained on this IRS page.
 US Expats Show Shocking Ignorance Of FATCA, 7 June 2018. Of course those who have a passport can give it up, read Why expat Americans are giving up their passports, 9 February 2016.
 Accidental Americans Financially Frustrated By FATCA, 22 April 2018.
 Euro MPs Want To Protect Accidental Americans Against FATCA, 16 July 2019.
 ‘Accidentals’ reel but vow to fight on, as France’s Conseil d’Etat rules in support of current FATCA regime, 20 July 2019. Earlier a procedure in the US was unsuccessful, according to this article: Repeal FATCA Appeal Rejected By US Supreme Court, April 4, 2018, but the opponents want to continue, FATCA Fight Will Carry On, Vow Repeal Campaigners, 21 February 2019.
 Like the EU Charter of Fundamental Rights, more information: European Union Agency for Fundamental Rights (FRA). Article 8, par. 2: “Such [personal] data must be processed fairly for specified purposes and on the basis of the consent of the person concerned or some other legitimate basis laid down by law. Everyone has the right of access to data which has been collected concerning him or her, and the right to have it rectified.“. Article 17, par. 1: “Everyone has the right to own, use, dispose of and bequeath his or her lawfully acquired possessions. No one may be deprived of his or her possessions, except in the public interest and in the cases and under the conditions provided for by law, subject to fair compensation being paid in good time for their loss. The use of property may be regulated by law in so far as is necessary for the general interest.”
Addition of 12 August 2019
After finishing this article I read an interesting article in German on the different systems in regard of nationality, Die Krux mit der Staatsbürgerschaft, DW 9 August 2019.