Last year it was Germany, and this year they have moved on to India.
Take a look at this link (EDIT: removed as dead). If you file your tripadvisor reviews via the Indian website, you will earn 100 Lufthansa Miles & More miles per review you submit.
It doesn’t matter that you don’t live in India! The miles are posting just fine for people, around three weeks after the end of the month in which you submit your review.
The small print references a closing date of 31th October, but that appears to be only for the competition they are also running. The 100 miles per review seems, for now, an on-going offer.