This article, “Flow-of-funds analysis at the ECB”, provides an excellent technical description of the European system for flow-of-fund statistics, and some good examples of how they are used at the ECB.
I would recommend it for anyone interesed in anyone doing SFC empirical modeling. It is a pity that the authors have not discovered yet the work of Godley and the book Monetary economics, which is well known at the Bank of England.