Lucas Di Grassi was the fastest driver after the opening 45-minute practise session around the short Monaco layout.
The season three champion set a 50.183 to be seven hundredths faster than Sam Bird and just over a tenth quicker than Mitch Evans in third.
Sebastien Buemi was fifth, sandwiched between Alexander Sims in fourth and Antonio Felix da Costa in sixth.
Robin Frijns would end the session seventh ahead of Andre Lotterer, with Oliver Rowland and Stoffel Vandoorne rounding out the top ten.
Reigning champion Jean-Eric Vergne just missed out on the top ten, Jerome D’Ambrosio finished twelfth, after leading the early part of the session. Jose Maria Lopez and Edoardo Mortara with Tom Dillmann rounding out the top 15.
Pascal Wehrlein ended 16th, ahead of Daniel Abt, Alex Lynn was 18th with Maxi Gunther 19th. Gary Paffett and Felipe Massa would end the times last of those who set a competitive time, as Oliver Turvey only did 7 laps, completing a time 3.6 seconds off the top, and 2.3 seconds behind 21st placed Massa.