Openly how?

Do you mean in public?

In front of other civilians?

While there were not as many open war crimes in the Western front as in the East, that is a combination of a few factors.

Perhaps most relevant, the fundamentals of Nazism were based on the idea of Slavic racial inferiority. Since they were viewed as subhuman, it was considered fine to execute them. In the West, combatants consisted of those not regarded as subhuman, so there was less of a preexisting excuse to commit massacres.

Further, it is well documented that the more difficult and brutal a war is, the more war crimes and atrocities are generally committed. This can be traced to difficult and bloody fighting creating a sense of frustration and anger among the soldiers. Perhaps the most prominent example would be the Rape of Nanking. In the proceeding months to the capture of Shanghai, Japanese soldiers were met with unexpectedly bloody fighting. While there were certainly massacres of partisans in France, and while incidents of fierce fighting did see massacres, they were further and fewer inbetween than in the East. The war in the West, , namely the battle of France, was without a lot of the attritional, bloody warfare.

But the Nazis were able to execute people in public in the West.

At Le Paradis, on May 27th, 1940, 100 retreating British soldiers were captured and summarily executed by the 3rd SS Panzer Division in front of a journalist (albeit, an SS journalist)

At Maille, on August 25th, 1944, the 17th SS Panzergrenadier division massacred 124 French civilians in reprisal for partisan attacks. They then burned the village to the ground.

At Tuile, in June of 1944, the 2nd SS Panzer Division massacred 117 French civilians, and then deported 150 more to Dachau, where 100 more died. All of this in reprisal for partisan operations.

Perhaps most terrible, at Oradour-sur-Glane, on June 10th, 1944, the 2nd SS Panzer Division, the same one who committed a massacre at Tuile, committed two separate massacres. At the Glane, they locked all women and children in a church and led the men to several barns. They used machine guns to shoot the men in legs, then set them on fire. After that, they went onto the church, where the women and children were sealed. They lit the building on fire, machine-gunning those who tried to escape. There was only one survivor. In total 642 French civilians were killed.

The Nazis, particularly the SS, were more than willing to massacre civilians in front of other noncombatants or in public places. But the extreme difficulty in the East and the deeply ingrained racial ideology made troops in the East far more willing to do so.