  To investigate if magnetic fields are present in Wolf-Rayet stars, we
selected a few stars in the Galaxy and one in the Large Magellanic Cloud (LMC).
We acquired low-resolution spectropolarimetric observations with the ESO FORS2
instrument during two different observing runs. During the first run in visitor
mode, we observed the LMC Wolf-Rayet star BAT99 7 and the stars WR6, WR7, WR18,
and WR23 in our Galaxy. The second run in service mode was focused on
monitoring the star WR6. Linear polarization was recorded immediately after the
observations of circular polarization. During our visitor observing run, the
magnetic field for the cyclically variable star WR6 was measured at a
significance level of 3.3sigma (<B_z> = 258+-78G). Among the other targets, the
highest value for the longitudinal magnetic field, <B_z> = 327+-141G, was
measured in the LMC star BAT99 7. Spectropolarimetric monitoring of the star
WR6 revealed a sinusoidal nature of the <B_z> variations with the known
rotation period of 3.77d, significantly adding to the confidence in the
detection. The presence of the rotation-modulated magnetic variability is also
indicated in our frequency periodogram. The reported field magnitude suffers
from significant systematic uncertainties at the factor 2 level, in addition to
the quoted statistical uncertainties, owing to the theoretical approach used to
characterize it. Linear polarization measurements showed no line effect in the
stars, apart from WR6. BAT99 7, WR7, and WR,23 do not show variability of the
linear polarization over two nights.
