Original tone mapped image by iCAM06 {p=536, ct=0.65}:

Histogram of the tone mapped image:

Image statistics of the tone-mapped image:

Median percentile of the lightness (CIE L*a*b*): 42.8612
Mean of the chroma value (CIE L*a*b*): 36.6313
Image produced by the generic tone mapping operator:
(evalution of the fit via PSNR: PSNR = 30.0983dB)

Fitted tone curve of the generic tone mapping operator,
compared to the luminance compression done by the tone mapping operator:

Fitted parameters of the generic tmo:

Exposure: 2.3197
Contrast: 0.6409
Low midtone range: 2.6388
High midtone range: 0.90828
Saturation: 0.62191
Frequencies: 1.573, 1.262, 1.22, 1.226, 1.167