The last trading day of June Dax, EuroSTOXX50 and Footsie futures are all 6/21, this Friday.
My pragmatic approach to rollover rules of any markets I trade is starting to list both months one week before the last trading day, and watching the change of trading activity which is reflected by the bid/ask spreads and trading volumes.
My experience/observation, without resorting to any written "rules" is that excepting for US markets which you know is the Thursday one week before the expiring week that is normally the third Friday week, and the rolling over that day is phenomenal, all major stock index futures worldwide roll over just one day before the last trading day, be it DAX, EuroSTOXX50, Footsie, Osaka's Nikkei 225, Kse Kospi 200, and all serial-month products such as CAC 40 and Hang Seng Index.
Personally I prefer to trade the near month till it's volume is surpassed by its succeeding one.
As you can see even today, only two days before the last trading day, June contracts of DAX, EuroSTOXX50 & Footsie are still dominant in trading volumes.