I find the solution reading this topic.
So here is my final request :
search * | rex field=_raw "(?<clientip>\d+\.\d+\.\d+\.\d+)" | lookup geoip clientip OUTPUT client_lat as lat client_lon as lon | table lat lon
the OUTPUT part seem to indicate which fields extract, and the table part put specifics fields on the response (only theses fields).
Here is my response (formatted into my controller) :
[[lon:2.0, lat:46.0], [lon:2.0, lat:46.0], [lon:2.0, lat:46.0], [lon:2.0, lat:46.0], [lon:-116.6167,
lat:31.8667], [lon:-116.6167, lat:31.8667], [lon:-116.6167, lat:31.8667], [lon:-116.6167, lat:31.86
67]]