Context : Many efforts are being made to characterize extrasolar planetary systems and unveil the fundamental mechanisms of planet formation .
An important aspect of the problem , which remains largely unknown , is to understand how the planet formation process depends on the mass of the parent star .
In particular , as most planets discovered to date orbit a solar-mass primary , little is known about planet formation around more massive stars .

Aims : To investigate this point , we present first results from a radial velocity planet search around red giants in the clump of intermediate-age open clusters .
We choose clusters harbouring red giants with masses between 1.5 and 4 M _ { \sun } , using the well-known cluster parameters to accurately determine the stellar masses .
We are therefore exploring a poorly-known domain of primary masses , which will bring new insights into the properties of extrasolar planetary systems .

Methods : We are following a sample of about 115 red giants with the Coralie and HARPS spectrographs to obtain high-precision radial velocity ( RV ) measurements and detect giant planets around these stars .
We use bisector and activity index diagnostics to distinguish between planetary-induced RV variations and stellar photospheric jitter .

Results : We present the discoveries of a giant planet and a brown dwarf in the open clusters NGC 2423 and NGC 4349 , orbiting the 2.4 M _ { \sun } -star NGC2423 No3 ( TYC 5409-2156-1 ) and the 3.9 M _ { \sun } -star NGC4349 No127 ( TYC 8975-2606-1 ) .
These low-mass companions have orbital periods of 714 and 678 days and minimum masses of 10.6 and 19.8 M _ { \mathrm { Jup } } , respectively .
Combined with the other known planetary systems , these detections indicate that the frequency of massive planets is higher around intermediate-mass stars , and therefore probably scales with the mass of the protoplanetary disk .

Conclusions :