boost local_date_time CET to UTC

I try to convert a boost local_date_time to UTC but I'm confused about the returned time of utc_time(). Here is a simplified code :

#include "boost/date_time/local_time/local_time.hpp"

int main()
{
  using namespace boost::gregorian;
  using namespace boost::local_time;
  using namespace boost::posix_time;

  ptime dt = ptime(date(2015, Mar, 2), hours(0));
  time_zone_ptr tz_cet(new boost::local_time::posix_time_zone("CET"));
  local_date_time local_dt = boost::local_time::local_date_time(dt, tz_cet);

  std::cout << local_dt << std::endl;
  std::cout << local_dt.utc_time() << std::endl;

  time_zone_ptr tz_utc(new boost::local_time::posix_time_zone("UTC"));
  std::cout << local_dt.local_time_in(tz_utc) << std::endl;
}

output:

2015-Mar-02 00:00:00 CET
2015-Mar-02 00:00:00
2015-Mar-02 00:00:00 UTC

UTC should be 1 hour behind CET (Central European Time).

Is this a bug or am I missing something?