French term (edited): banquetage

It looks to me as though this is what they mean. In your reference the banquetage is shown in the photo as a pair of horizontal boards fixed to stakes marking the corners of the building. Here's another similar source with a photo (scroll down a little to see it). Note the horizontal strings fixed to the boards in this case:

"Implantation de précision sur banquetage
- Implantation précise des axes de la construction."
http://www.infogeo.ch/?page_id=60

And here are batter boards, illustrated with a drawing:

"batter boards
Definition
Pairs of horizontal boards nailed to wood stakes adjoining an excavation. Used with strings as a guide to elevation and to outline a proposed building. The strings strung between boards can be left in place during excavation."
http://www.dictionaryofconstruction.com/definition/batter-bo...

Further details in this book:
https://books.google.es/books?id=8SJHAAAAQBAJ&pg=PT320&lpg=P...

My one reservation is that batter boards seem to be put in place after staking out but before excavation, whereas the banquetage seems to be placed after excavation. But I can't find anything like this in EN sources placed after excavation, and batter boards are probably the nearest we can get.

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Note added at 2 hrs (2015-10-22 02:06:32 GMT)
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I meant to put "a pair of horizontal boards at 90 degrees" in the first paragraph above.

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Note added at 11 hrs (2015-10-22 11:00:10 GMT)
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I've just seen Donal Lyons' answer, which mentions profile boards. That is what these are; it's an alternative term for batter boards. The illustrated sources for baquetage demonstrate that it refers to these boards which mark the "axes de la construction".