There are two species of Treecreeper in Europe, there is the Treecreeper (Certhia familiaris) and also the Short-toed Treecreeper (Certhia brachydactyla)
The difference between them is not the length of their toes but the length of their claws. My wife says typical of bird names….. The Grey Wagtail is Yellow and the Black headed Gull has a brown head and then for only some of the year and a Common Gull is not so common etc etc
Also the Short-toed treecreeper has a sligtly more buff colour to its sides and its face has less white on it than the Treecreeper. However if you see a Treecreeper in Poitou-Charentes then it will almost certainly be Short-toed. This is because the Short-toed treecreeper lives in Western Europe, whereas the Treecreeper lives in Eastern Europe and Britain and the two do not generally overlap and certainly not in this region.
Now these little birds are very poor at flying. The way they get about is to creep up to near the top of a tree and then fly diagonally down to a nearby tree. Then they climb up this tree and fly down to the next tree and so on and so on. As they climb up each tree they are searching the the bark for insects and other tasty invertebrates. As a consequence of this lack of flying ability they are obviously restricted to woodland or regions where trees are fairly close together. They will use walls in the same way as a tree trunk and especially attrctive are old walls typical of this area which also might harbour plenty of bugs.