  We report the discovery of two new exoplanet systems around fully convective
stars, found from the radial-velocity (RV) variations of their host stars
measured with the nIR spectropolarimeter CFHT/SPIRou over multiple years. GJ
3378 b is a planet with minimum mass of $5.26^{+0.94}_{-0.97}$ Mearth in an
eccentric 24.73-day orbit around an M4V star of 0.26 Msun. GJ 1289 b has a
minimum mass of $6.27\pm1.25$ Mearth in a 111.74-day orbit, in a circular orbit
around an M4.5V star of mass 0.21 Msun. Both stars are in the solar
neighbourhood, at respectively 7.73 and 8.86 pc. The low-amplitude RV signals
are detected after line-by-line post-processing treatment. These potential
sub-Neptune class planets around cool stars may have temperate atmospheres and
be interesting nearby systems for further studies. We also recovered the
large-scale magnetic field of both stars, found to be mostly axisymmetric and
dipolar, and with a polar strength of 20-30 G and 200-240 G for GJ 3378 (in
2019-21) and GJ 1289 (in 2022-23), respectively. The rotation periods measured
with the magnetic field differ from the orbital periods, and in general,
stellar activity is not seen in the studied nIR RV time series of both stars.
GJ 3378 b detection is not confirmed by optical RVs and is therefore considered
a candidate at this point.
