This entry needs to be changed a bit:
1. The Swiss version should have the same translations as the version with a K.
2. I think the "decollete" with no accents is AmE: it is in Merriam-Webster (for the noun, see below) but not in my Oxford Dictionary of English. This also has "décolletée" (two Es) for the noun or adjective.
3. Even Merriam-Webster doesn't have "decollete" with no accents for the adjective:
Main Entry: 1dé·col·le·té
1 : wearing a strapless or low-necked dress
2 : having a low-cut neckline
Main Entry: 2décolleté
Variant(s): also de·col·le·te
4. You could add the translation "décolletage":
Main Entry: dé·col·le·tage
1 : the low-cut neckline of a dress http://www.merriam-webster.com/dictionary/dec...
Oxford Dict of E: ... a low neckline on a woman's dress or top.