The views from the terrace of Basilique de Notre Dame de Fourvière are amazing with clear sights of Cathédrale St Jean, Place Bellecour, the 'Crayon' skyscraper, and the control tower of St Exupéry airport. Only from this place can you appreciate the immense size of Lyon.
It's also a great starting point for a walking tour of Fourvière.
Just follow signs for Basilique de Notre Dame de Fourvière from Place Bellecour or take the funicilar from Vieux Lyon métro station
This tip's title is a bit misleading. The view is from adjacent to Fourvière cathedral on top of the hill, not St Jean which is in Vieux Lyon at the bottom of the hill.