Yed. The flowerbed with Dahlias in bloom in late summer is fully handicap accessible. There is legal parking on the street nearby and sidewalks to the Dahlias as well as the nearby Conservatory of Flowers.
Parking varies in the park, there are some spots in front of the Conservatory of Flowers. Yes the gardens are completely accessible. If you google photos you will see the area is on flat, paved road.
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