Likely paved area, may be a (disused) sports pitch.

Imagery: Bing, Maxar Premium

Empty, mostly fenced area may be a recreational area. The small paved area may be a (disused) basketball pitch.
Unfortunately any details are not clearly visible, or are lacking due to lack of resources.

Imagery: Maxar Premium -any aerial imagery-

The abandoned railway bridge seems to start at this point.

Imagery: Esri Clarity, Esri

Railway gets narrower(?) starting at this point. Not sure if this is something which can be mapped.

Imagery: Esri Clarity, Esri

Railway seems to stop at this point.

Imagery: Esri Clarity, Esri

Missing pitches of unknown type.
If you know it, add it! :-)

Une des entrées du parc, non directement visible sur les photos aériennes.

Mapillary 2017-11-18 par fgouget
https://www.mapillary.com/app/?pKey=916192472584874&focus=photo