This is the segment with the famed ladder section (watch a video of it here), which is not recommended for those with an extreme fear of exposure.
This section offers spectacular views of Mont Blanc, and although it tends to be the last leg of the tour for many tired hikers, we don't recommend skipping it. But if you have to skip it, it is possible to take a train from Montroc to Chamonix, and then maybe take a cable car up La Flégère for the views.
We recommend getting an early start on the ladders, as they can become quite backed up once two-way traffic increases later in the day.
Update: Both Refuge La Flégère and the La Flégère cable car will be closed in 2019.
It is possible to end the tour here and take the La Flégère cable car down to Chamonix.
To avoid the ladder section, walk down the main road toward Chamonix for a few minutes from the Trélechamps bus stop, until you reach a point where a gravel road comes in from the left, and a foot path ascends to the right. This footpath will lead to Bois de la Trampe, and from there you can ascend to La Flégère.