Samuel, it is a grim but indeed most intriguing topic. I am glad to answer your request by sharing references from misc. notes on this over the past 7 or 8 years, and I found that by using the search feature here on this forum...if you pull up "European Executioner Sword" (12/10/06) you will see an extensive discussion that took place back then.
In retrieving my notes and reviewing that thread I found some additional information your colleague might find useful.
It was suggested that actual executioner swords had lenticular section blades contrary to the lozenge type of true combat weapons. These also were inclined to have the balance toward the tip, thus making them quite unsuitable for actual combat. Apparantly in literature there were some cases of writers suggesting that headsmen also used thier swords in combat, which by this note was patently incorrect.
Apparantly among European executioners with the sword, the French were the most proficient, and the Sanson family most renowned having some seven generations in this macabre profession. The only instance of a sword being used in England for execution was that of Anne Boleyn (1536) by her request, and for this the headsman was brought from France. The sword used as a 'bearing sword' in England from the time of Henry III was named 'Curtana' (=cut short) and had the squared tip. Termed 'sword of mercy' it was not used for executions.
As mentioned, while France apparantly was known for proficiency, the swords themselves are typically found to be of German make.
For your convenience, the best references are as follows:
"European Arms and Armour" Claude Blair, #82 (Tower of London item IX875)
a German example c.1600
"Torture and Punishment" (Royal Armouries publ. p.19)
"Encyclopedia of Arms and Armour" Tarussul & Blair p.51
"Swords, Daggers and Cutlasses" G. Weyland, p.26
"Cut and Thrust Weapons" E. Wagner, Prague, 1967, plate 34
and associated text (cross referenced)
"Wallace Collection , European Arms and Armour" Sir James Mann, 1962
A721 c.1540 German
A722 c.1561 German
A723 c.1610
A724 c.1620 Hungarian?
pp.367-369
"Capital Punishment" David Padfield, 2004
"Edged Weapons" Frederick Wilkinson, 1970, p.19, 25 fig. 14 by Johannes Wundes, Solingone, also fig.21
In Germany, contact:
Kriminalmuseum
D-9154 Rothenburg
Burgasse 3-5 Germany
info@kriminalmuseum.rothenburg.de
For information on the "Vehmic Courts" which were technically 'League of the Holy Court Vehmgericht (Vehm)" use the following course.
These were secret tribunals of Westphalia from the time of the Middle Ages, apparantly principally seated in Dortmund. As mentioned, these 'Free Judges' were represented in many principalities in Germany and may have used such swords as symbols of authority, including orders of execution. Symbolism seen on these blades often used the letters 'S S' (=sacrificum sanctum)
three crosses (of atonement, Luke23:32-33) and other of previously noted symbols.
Hopefully these details and references might offer a benchmark for your colleague to continue research on the interesting weapon you have posted and possibly associated material.
All the best,
Jim