Although the Belgian's M-Sport Ford was not fastest on any of the three stages as the recovering Sebastien Loeb and Sebastien Ogier took the wins, he still extended his overall advantage to 13.1 seconds.
It had been as high as 16s before a small error on the loop-closing Soultzeren stage cost Neuville a little time.
Jari-Matti Latvala is now second, edging his Volkswagen ahead of Dani Sordo's Citroen by 1.1s during the morning.
Loeb's farewell World Rally Championship event got a bit tough when he spun on the exit of a hairpin on SS9.
That cost him 10s and briefly dropped him behind new champion Ogier, who won the first two stages as he made up for his disappointing Friday.
Loeb's Soultzeren win swapped their positions again, meaning the Citroen driver finished the morning 19.8s off the lead and 5.6s behind third-placed Sordo, with Ogier another 3.6s back.
An over-cautious start from Evgeny Novikov looked like it might put his sixth place in jeopardy, but he then responded to pull away from Mikko Hirvonen, Mads Ostberg and Andreas Mikkelsen again.
Robert Kubica continues to lead WRC 2 by three minutes.