You can explicitly set which font family is picked up for a given font style (e.g., ‘serif’, ‘sans-serif’, or ‘monospace’).
In the example below, we only allow one font family (Tahoma) for the sans-serif font style. You the default family with the font.family rc param, e.g.,:
rcParams['font.family'] = 'sans-serif'
and for the font.family you set a list of font styles to try to find in order:
rcParams['font.sans-serif'] = ['Tahoma', 'DejaVu Sans',
'Lucida Grande', 'Verdana']
from matplotlib import rcParams
rcParams['font.family'] = 'sans-serif'
rcParams['font.sans-serif'] = ['Tahoma']
import matplotlib.pyplot as plt
fig, ax = plt.subplots()
ax.plot([1, 2, 3], label='test')
ax.legend()
plt.show()