import numpy as np
import pandas as pd
import matplotlib.pyplot as plt
import matplotlib.font_manager as font_manager
df = pd.DataFrame(data=np.random.random((2, 2)), columns=['\xe9',
    '\u65e5\u672c'])
ax = df.plot()
legend = ax.legend()
font = font_manager.FontProperties(fname=
    '/Users/user/Downloads/IPAfont00303/ipag.ttf')
for text in legend.texts:
    text.set_font_properties(font)
plt.show()
Отображать не ascii (японские) символы в легенде сюжета pandas