This is a small (8 cm) Grand Pressigny dagger from the Lac de Neuchatel found by an enthousiastic amateur during the late 19th century whithout any contexttual information. It seems that this small artifact was the end-product of repeated reworking.
The “Grand Pressigny phenomenon”, early described in the 1860ies (http://jimmcneill.wordpress.com/2012/01/21/palaeolithic-worked-flint-tools-grand-pressigny-a-short-paper-by-john-evans-1823-1908/) is characterized by the production of thousands very long flint blades, made from the yellow wax-coloured flint from Grand-Pressigny area and their abundant and wide-ranging distribution (longest distance: 970 km) across Europe. This phenomenon is dated to the end of the third millennium.
In N/W-Europe Grand Pressigny daggers are associated with male graves during the later part of the Single Grave Culture, between c. 2650-2400. There is every reason to assume that during the following Bell Beaker Culture period (c. 2400-1900 BC) copper daggers replaced these flint daggers as prestige items and status indicators (http://www.aggsbach.de/2012/08/the-bell-beaker-phenomenon/).
Some 1000 pile dwelling sites, dated to the middle and late Neolithic and even inhabited at several stations until the Iron age, are known from around the Alps. They are spread across Switzerland, southern Germany, Austria, Slovenia, northern Italy and eastern France. They are often located on the shores of lakes, in the boggy areas of dried up bodies of water and, more rarely, in the flood plains of rivers. Due to their location in waterlogged soil, constructional timbers, food remains, wooden tools and even items of clothing have survived. Therefore, these settlement remains offer more detailed insight into the prehistoric lifestyle: they are the most important sources for research into early farming communities in Europe.
In what is now Switzerland, the Grand Pressigny daggers are dated between 2750-2500 and were found at many prehistoric lake-side villages from the hilly Mittelland region, which stretches from Lake Constance to Lake Geneva. Besides Grand Pressigny flint and local chert sources, high-quality imported flint from other equaly far-off deposits was also used (Rijholt, NL; Meusnes, Origny, Mont Ventoux, FR; Monte Baldo and Monte Lessini, IT).