diff --git a/.circleci/config.yml b/.circleci/config.yml
index d65d50f8..86f6234b 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -29,7 +29,7 @@ jobs:
       - run: pip3 install .[all]
       - run: pip3 check
       # format and lint
-      - run: black --check setup.py matplotlib2tikz/ test/*.py
+      - run: LC_ALL=C.UTF-8 black --check setup.py matplotlib2tikz/ test/*.py
       - run: flake8 setup.py matplotlib2tikz/ test/*.py
       # The actual test
       - run: cd test/ && MPLBACKEND=Agg pytest --cov matplotlib2tikz
diff --git a/README.md b/README.md
index f8ad63d3..e2f85fe5 100644
--- a/README.md
+++ b/README.md
@@ -30,20 +30,21 @@ For example, the matplotlib figure
 import matplotlib.pyplot as plt
 import numpy as np
 
-plt.style.use('ggplot')
+plt.style.use("ggplot")
 
 t = np.arange(0.0, 2.0, 0.1)
-s = np.sin(2*np.pi*t)
-s2 = np.cos(2*np.pi*t)
-plt.plot(t, s, 'o-', lw=4.1)
-plt.plot(t, s2, 'o-', lw=4.1)
-plt.xlabel('time (s)')
-plt.ylabel('Voltage (mV)')
-plt.title('Simple plot $\\frac{\\alpha}{2}$')
+s = np.sin(2 * np.pi * t)
+s2 = np.cos(2 * np.pi * t)
+plt.plot(t, s, "o-", lw=4.1)
+plt.plot(t, s2, "o-", lw=4.1)
+plt.xlabel("time (s)")
+plt.ylabel("Voltage (mV)")
+plt.title("Simple plot $\\frac{\\alpha}{2}$")
 plt.grid(True)
 
 from matplotlib2tikz import save as tikz_save
-tikz_save('test.tex')
+
+tikz_save("test.tex")
 ```
 (see above) gives
 ```latex