Context :

Aims : Our aim is to constrain the properties of dark matter halos inhabiting high density environments , such as is the case in massive galaxy clusters .

Methods : We use galaxy-galaxy lensing techniques that utilize a maximum likelihood method to constrain the parameters of the lenses .
It has been demonstrated that such a technique provides strong constraints on the parameters that characterize a galaxy halo , as well as on the aperture mass of these halos .
In this analysis , we only use weak shear data and do not include strong lensing constraints .

Results : We present the results of a study of galaxy-galaxy lensing in a homogeneous sample of massive x -ray luminous clusters at z \sim 0.2 .
These have been observed in three bands with the cfh12k instrument .
We find dark matter halos in these clusters to be compact compared to those inferred around isolated field galaxies of equivalent luminosity at this redshift : the half mass radius is found to be smaller than 50 kpc , with a mean total mass of order 0.2 \cdot 10 ^ { 12 } M _ { \sun } .
This is in good agreement with previous galaxy-galaxy lensing results and with numerical simulations , in particular with the tidal stripping scenario .
We thus provide a strong confirmation of tidal truncation from a homogeneous sample of galaxy clusters .
Moreover , it is the first time that cluster galaxies are probed successfully using galaxy-galaxy lensing techniques from ground based data .

Conclusions :