Hello everybody.
I'm not going to tell you how to do this achievement because the other two solutions are great enough.
However, many people are having a lot of trouble finding the last one they need.
Here is a little thing that
MAY help you but be carefull with it.
You should register onhttp://sleepingdogs.netYou'll have to link your XBL account to your Square Enix account. You may have to log out and log in again after that because it may not update the site correctly.
This site shows you what events you've already done so far... at least it's supposed to.
Unfortunately for many players the infos it shows are not updated or totaly broken.
As far as I'm concerned, I only missed one event before I went to check on the site and the event I was missing was the only one the site was telling me I had done...
So I give you this tip because
if you're lucky it can be an awesome help.
But please don't make the same mistake I did: don't believe it at 100%. Take 5 mins to check the events even if the site tells you that you've already done them.
PS: Please correct me if I've done english mistakes :)