import seaborn as sns

ax = sns.regplot(x='Col1', y='Col2', data=df_tot)

# we can use more features

import matplotlib as mpl
import matplotlib.pyplot as plt

plt.figure(figsize=(15, 10))     # bigger graph

sns.set(font_scale=2)     # bigger fonts
sns.set_style('whitegrid')     # white background

# make "+" green bigger marker (with marker, color e scatter_kws options)
ax = sns.regplot(x='Col1', y='Col2', data=df_tot, color='green', marker='+', scatter_kws={'s': 200})
ax.set(xlabel='COLUMN 1', ylabel='COLUMN 2')      # axis labels
ax.set_title('TITLE')       # graph title