That's what I thought, you have no credible citation. You can't even post a link to the Index showing it's on there.
The Index (1948) that I posted doesn't have the City of God on there, unless I missed it.
"whatever argumentation can be raised against the book" ... LOL, yeah, the only "argumentation" that can be raised against the book is that the details of the lives of Blessed Mary and Jesus are "too concrete". The criticisms don't mention any of the actual details. Where's the heresy? Where's the scandal? Give us some details. They've already been outlined for decades in Valtorta's and Faustina's productions.
Get to work.
The book was not on the Index in 1948 (I already mentioned that it was Indexed in 1681, and then subsequently “rehabilitated”);
It was condemned by 102 of 150 doctors of theology at the Sorbonne, and provided the link where this info is contained in the 2nd post of this thread, as well as the reasons for that condemnation;
It was also mentioned in the same first two posts of this thread (which contained links to each article) that not only was the cause for canonization of Mary of Agreda definitely halted because of this book, but also that even Cardinal Ratzinger and the conciliarists take issue with it.
Bishop Tissier de Mallerais also sponsored and endorsed a book in 1993 by a French SSPX priest cautioning the faithful against these books.
If in order to clear the Mystical City, you wish to dispute the veracity of the citations or claims of these authors, please do so.