Give figures in Swiss francs, then euros in brackets. 

"Five grams of enriched lead for the accelerator costs 12,000 CHF (€9700)," says Kuchler. 

Use symbols and numerals when quoting specific amounts of common currencies:

£5 million (not 5 million pounds, or five million pounds)

€5 (not 5 euros or five euros)
about $3.5 billion (not about 3.5 billion dollars)

The same applies to Canadian dollars (CAN$), Australian dollars (A$) and New Zealand dollars (NZ$).

Where you do need to spell out the currency unit, when talking about vague amounts, it is always lower case:

The floods in 2002 cost Germany billions of euros

On the rare occasions when you will need to use other currencies, they should be spelled out:

35,000 yen
1.6 million roubles

Unlike other units, no hyphens are needed in: “a £50 million project”