Merci. I'll start in English; I may switch to French.
First of all, it should be said that not every country on this planet has a state immunity act. In fact we are part of the minority. It is chiefly common-law-based countries, ironically, who have shied away historically from codification, who have state immunity acts: Canada, the U.S., the U.K. But some Commonwealth countries don't have a state immunity act, New Zealand being a chief example. They proceed and they deal with immunities on the strict basis of common law, customary norms being automatically incorporated as part of the common law. So that's how they do it. It's quite simple and straightforward, really.
Ironically, most civil law countries do not—for example, continental Europe. In fact none of them, to my knowledge, have state immunity legislation. France, Belgium, Italy, and Spain don't have state immunity laws. They do it as a basis of strict law, international law that they apply through their domestic courts. They don't have the conundrum of adjusting their national legislation to international norms. They just do it as a matter of law, quite simply.
An interesting case study I would like to bring to your attention is a litigation between Italy and Germany. I think the first case was in 2004. Actually it started way before that, but it was brought to the Corte Suprema di Cassazione, the Supreme Court of Italy, in 2004. It was called the Ferrini case, Ferrini v. Germany. Here was a man who was basically suing for war crimes and other atrocities, including torture, during World War II. He was deported to Germany, interned in camps, and forced to work. Here he is in the 21st century suing Germany, who incidentally, it should be pointed out, has been Italy's primary trading partner. They're great friends, and here Italian courts are entertaining a lawsuit against Germany for these atrocities that happened, and without the benefit of the state immunity legislation, strictly on the basis of customary international law. The Corte Suprema di Cassazione realized it in a judgment that has since been upheld 14 other times. So now there are 15 Italian judgments all recognizing that there is no immunity in international law for crimes against humanity and for these jus cogens offences, universal jurisdiction crimes. That's an important precedent to keep in mind.
Germany and Italy still to this day remain great friends. I went this morning to the website of the German foreign office, and there's a tab for every country of the European Union and the tab for Italy is all rosy. They maintain how their relationships are as strong as ever, despite their obviously having a disagreement on the extent of the immunity that should be given to those particular acts.
It's an interesting precedent to be borne in mind as not being fatal to foreign relations.