Bank customers queue at a Paris ATM during a strike by money delivery crews

PARIS, France (CNN) -- With a hand on his revolver, one security man stands guard as another picks up and drops off bags of cash and a third waits in an armoured truck with the engine running.

It's a task this money-delivery crew carries out regularly with military-style precision.

But the work of this crew and others will double during the euro rollout -- the largest movement of money in human history -- and those responsible for the delivery of the new notes and coins are more than nervous.

Just in France, 7.6 billion euro coins and 2.2 billion euro notes -- weighing 72,000 tons, or the equivalent of three Eiffel Towers -- will be transported to banks and retailers over six months starting in early September.

"It's about our security, our working conditions. It's out of the question to work a guy to death carrying tons and tons of money day in day out," says Jacques Charles, a Brink's driver and union leader.

"Risk zero just does not exist, that's for sure. Unfortunately the level of crime has increased significantly in Europe in general, and France especially, over the last years and the last months," says Jean-Michel Houry, vice president and managing director for Brink's Europe.

There have been more than 300 attacks during money deliveries over the past five years in France.

In the last two years, 13 guards have been killed, and there have been two nationwide strikes by armoured car crews in protest.

The strikes caused acute shortages of cash at banks and ATMs, and they would be a nightmare if repeated during the period when the new euros are to be delivered.

Charles has seen several of his colleagues killed or injured in hold-ups.

"I can tell you one thing, if there's a fatal attack because of the euro, we will all stop work. If there's not enough security there'll be no exceptions, no deals," he says.

Security is, of course, the nature of Brink's business. It has half the market in France.

To handle the massive euro workload, Brink's has reinforced its trucks, bought new ones and hired an extra 400 staff -- mostly ex-military. They've also increased firearms training.

It's an investment of almost $15 million, but one which some in the industry say may not be enough given the heavy firepower of some of the gangs and nationalist groups.

In one attack near Paris, rocket-propelled grenades were used to net millions of francs. Police were able to make arrests within hours, and much of the money was recovered.

Given the threat to security crews and the threat of a strike, it's likely the government will agree to help by providing police or military escorts.

Any disruption in the transition to the euro would be a worse scenario than having the army on the streets of the French capital.