i’ve dealt with lapierre warranty a number of times and they are pretty efficient, usually photo’s will do and they generally don’t ask for the frame for inspection just for the failed frame to be returned.
the 2013 carbon frames did have issues or more accurately the replacement articulation spacers did once the originals wore out, the replacements were too small causing them to rotate in the frame rather than the insert rotating in the spacers.
the 2014> frames have been bombproof, not seen a single failure of any kind on one yet including my own 527 which ha a harder life than most bikes.