When you are in Paris. Sacré-Cœur is the place that you must visit. But when visit Sacré-Cœur, you should be careful of the people outside the Sacré-Cœur, they will force you to buy something that you don't want.
When I was in High school.The geography text book will introduce the Paris, this photo of Love Wall always show on it. If you want to visit Sacré-Cœur, the wall is just on the side when got out the subway station.