The hardest part may be finding the car park. You could start from the town hall car park, but this adds a lot of tarmac.
After passing the town hall of Brison-Saint-Innocent on your left, the school on your right and the cemetery on your left, take the second street on the right (Chemin des Gros) and follow it to the end through the vineyards.
(D/) From the car park, which has no more than four or five spaces, head south along the narrow road lined with vineyards on the right. After 500 metres, turn left.
(1) Take a path hidden by foliage. At first, it climbs steeply and then more moderately, passing through boxwood trees. When you emerge onto flat ground, cross a botanical garden where various species of trees are on display, then join point 439 on a stony track (a place called Les Branles).
(2) Turn left north onto the track and continue to point 522.
(3) Take the path that climbs to the right towards the Grotte des Fées.
You will reach a crossroads.
(4) Make a round trip to the cave (a viewpoint sign indicates the direction).
Return to the crossroads and continue climbing up the track that branches off to the left (north).
Follow this track through the forest for about 1 km - yellow markings - and you will reach a junction.
(5) Leave the path that climbs up to the Croix de Meyrieu on your right and descend to the left towards the hamlet of Les Granges de Brison. Along the way, pass a clearing with a viewpoint and further down, leave a path that branches off to the left.
(6) Continue to the hamlet of Les Granges de Brison and, at a hairpin bend, leave the road and head south.
(7) Head south along a pleasant grassy path, which becomes stony as it winds its way down a series of hairpin bends.
Stay on the path that crosses vineyards and return to the car park (S/E).