Most observances were held online, due to the coronavirus pandemic, and only few people attended the ceremony at the monument.
In Israel, some 900 Holocaust survivors died from COVID-19 out of 5,300 who were infected last year.
Israel, which counts 197,000 Holocaust survivors, officially marks its Holocaust remembrance day in the spring.
Meanwhile, Luxembourg signed a deal agreeing to pay reparations and to restitute dormant bank accounts, insurance policies and looted art to Holocaust survivors.
Of the 6 million Jewish victims, some 1.5 million were children, and this year's commemorations included a special focus on them.