diff --git a/rrd/export-rrd.py b/rrd/export-rrd.py
index 5da8c60..78c44c9 100755
--- a/rrd/export-rrd.py
+++ b/rrd/export-rrd.py
@@ -1,128 +1,128 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 """Script to execute the export of softwareheritage's rrds data.
 
 """
 
 import click
 import json
 import os
 import subprocess
 
 
 DIRPATH='/var/lib/munin/softwareheritage.org/'
 FILENAME_PATTERN="prado.softwareheritage.org-softwareheritage_objects_softwareheritage-###-g.rrd"
 # The data source used at rrd creation time
 DS=42
 
 ENTITIES=[
     "content",
     "origin",
     "revision",
     # "directory_entry_dir",
     # "directory_entry_file",
     # "directory_entry_rev",
     # "directory",
     # "entity",
     # "occurrence_history",
     # "person",
     # "project",
     # "release",
     # "revision_history",
     # "skipped_content",
     # "visit",
 ]
 
 def compute_cmd(dirpath,
                 start,
                 step=86400):
     """Compute the command to execute to retrieve the needed data.
 
     Returns:
         The command as string.
 
     """
     cmd = ['rrdtool', 'xport', '--json', '--start', str(start), '--end', 'now-1d',
            '--step', str(step)]
     for entity in ENTITIES:
         filename = FILENAME_PATTERN.replace('###', entity)
         filepath = os.path.join(dirpath, filename)
 
         if os.path.exists(filepath):
             cmd.extend(['DEF:out-%s1=%s:%s:AVERAGE' % (entity, filepath, DS),
                         'XPORT:out-%s1:%s' % (entity, entity)])
 
     return cmd
 
 
 def retrieve_json(cmd):
     """Given the cmd command, execute and returns the right json format.
 
     Args:
         cmd: the command to execute to retrieve the desired json.
 
     Returns:
         The desired result as json string.
     """
     cmdpipe = subprocess.Popen(cmd, stdout=subprocess.PIPE)
-    data = ''
+    data = b''
     while True:
         line = cmdpipe.stdout.readline()
         if not line:
             break
         # Hack: the json output is not well-formed...
-        line = line.replace('\'', '"')
-        line = line.replace('about: ', '"about": ')
-        line = line.replace('meta:', '"meta": ')
+        line = line.replace(b'\'', b'"')
+        line = line.replace(b'about: ', b'"about": ')
+        line = line.replace(b'meta:', b'"meta": ')
         data += line
 
     cmdpipe.stdout.close()
-    return json.loads(data)
+    return json.loads(data.decode('utf-8'))
 
 
 def prepare_data(data):
     """Prepare the data with x,y coordinate.
 
     x is the time, y is the actual value.
     """
     # javascript has a ratio of 1000...
     step = data['meta']['step'] * 1000  # nb of milliseconds
     start_ts = data['meta']['start'] * 1000  # starting ts
 
     legends = data['meta']['legend']
 
     # The legends, something like
     # ["content-avg", "content-min", "content-max", "directory_entry_dir-avg", ...]
     r = {}
     day_ts = start_ts
     for day, values in enumerate(data['data']):
         day_ts += step
         for col, value in enumerate(values):
             if value is None:
                 continue
             legend_col = legends[col]
             l = r.get(legend_col, [])
             l.append((day_ts, value))
             r[legend_col] = l
 
     return r
 
 
 @click.command()
 @click.option('--dirpath', default=DIRPATH, help="Default path to look for rrd files.")
 @click.option('--start', default=1434499200, help="Default starting timestamp")   # Default to 2015-05-12T16:51:25Z
 @click.option('--step', default=86400, help="Compute the data step (default to 86400).")
 def main(dirpath, start, step):
 
     # Delegate the execution to the system
     run_cmd = compute_cmd(dirpath, start, step)
     data = retrieve_json(run_cmd)
 
     # Format data
     data = prepare_data(data)
 
     print(json.dumps(data))
 
 
 if __name__ == '__main__':
     main()