The device timezone can be changed.

To set the timezone to Europe/Paris, do:

vrouter running config# system
vrouter running system# timezone Europe/Paris
vrouter running system# commit

To display the timezone state, and the date:

vrouter> show state / system
   timezone Europe/Paris
   date "Fri Jul 13 10:53:46 2018"

The same configuration can be made using this NETCONF XML configuration:

vrouter running system# show config xml absolute
<config xmlns="urn:6wind:vrouter">
  <system xmlns="urn:6wind:vrouter/system">