Here is how the sales, which stretch four days from Black Friday to Cyber Monday, are expected to fare in some of the continent's big spenders:

France

After starting in 2015, the concept of Black Friday sales has now been taken up by all major retailers after wavering in the wake of the Paris attacks in November 2015.

The French are expected to spend €845 million ($1 billion) online this weekend, a 15 percent increase since 2016, and €4.5 billion in stores, a four percent rise, according to a report by the Centre For Retail Research for the Poulpeo website.

But buyers beware — the government website cybermalveillance.gouv.fr has urged all shoppers to be wary during the sales, when scams by cybercriminals multiply.

Some have also warned of the dangers of over consumption. Envie, a network of 50 French companies, launched a “Green Friday” initiative, while the Camif website closed on Friday, saying it was “fed up”.

Germany

Shoppers in Germany have been seduced by the sales for several years.

Last year, 16 percent of consumers participated in the sales on Black Friday and 13 percent on Cyber Monday, spending a 1.7 billion euros, according to the German retail federation.

However US online retail giant Amazon faces strikes by 2,000 at six of its warehouses in Germany by employees demanding better working conditions, according to trade union Verdi.

Spain

Black Friday took off in Spain in 2012, when labour reforms liberalised sales.

Nine out 10 companies will participate in the sales this year, according to the Spanish Digital Economy Association. Even banks are joining in, offering discounted credit cards and home loans.

The average Spanish shopper is expected to spend 222 euros during the sales, up from 200 last year. Sales country-wide could reach 1.4 billion euros.

Faced with this rising consumption, some associations have encouraged people to boycott the sales, with little success.

Italy

Fourteen million Italians will take advantage of the sales on Friday, according to leading local business association Confesercenti. A total of €1.5 billion is expected to change hands — an average of €108 per person.

Most of the sales take place online, but Black Friday is gradually gaining acceptance in brick-and-mortar stores, with seven out of 10 making special offers this year.

Along with Germany, some Italian Amazon workers will also go on strike at a distribution centre in Castel San Giovanni in the country's north.

Greenpeace activists also protested in a Rome shopping centre, using the symbol of a globe suffocating under the weight of consumer goods.

Britain

After a drop in the value of the pound, British shoppers may well welcome this year's sales.

Britons are expected to spend £2.6 billion (€2.9 billion, $3.4 billion) this Friday, up eight percent from last year, according to forecasts by VoucherCodes and the Centre for Retail Research.

Over the four days, as much as €7.8 billion will be spent — an increase of seven percent.