German supermarket chain Aldi has begun High Court action against Dunnes Stores over the use of its name and prices in Dunnes' advertising.
Aldi claims Dunnes has infringed on its trademarks with ads comparing prices for a range of grocery items.
It claims Dunnes' ads are not fair because it is not comparing like-for-like products.
Aldi says Dunnes is entitled to use the trademarks to compare goods.
However, it says the manner in which they were used did not comply with Consumer Protection legislation or with European Community regulations.
It says Dunnes' ads conveyed the impression that its products were cheaper than Aldi's.
Aldi says a number of the products were not cheaper and at best they were the same price.
It says the ads also conveyed the impression that Dunnes' products were generally cheaper than those of Aldi and it says Dunnes has no basis for such a claim.
The case was admitted into the Commercial Division of the High Court.