I decided to study a little bit carefully the subject and to do an article, both in French and in English. So it will take a few days : Here is something that I give you in advance :
Denzinger in English (go to number 2296)
http://www.catecheticsonline.com/SourcesofDogma.phpMillenarianism (Chiliasm) *
[Decree of the Holy Office, July 21, 1944]2296 In recent times on several occasions this Supreme Sacred Congregation of the Holy Office has been asked what must be thought of the system of mitigated Millenarianism, which teaches, for example, that Christ the Lord before the final judgment, whether or not preceded by the resurrection of the many just, will come visibly to rule over this world. The answer is: The system of mitigated Millenarianism cannot be taught safely.
Latin :Systema Millenarismi mitigati tuto doceri non posse.This answer was confirmed by the Holy Father Pius XII, adds the French Denzinger in its N°3839
http://catho.org/9.php?d=bxh#e5n