The aim of this work is to find out a comparative method for an ecological assessment of a (retrographic) sheet of paper based on the biopolymer PLA and based on normal pulp. Therefore a product life cycle was made for both cases, which analyses and ecobalances the mass flows, the energy flows and production processes themselves. This is needed as basis to make a comprehensive life cycle assessment for assessing the environmental aspects associated with a product over its life cycle. That LCA (= eco balance) provides therefore a ecological visiting card of both products and eventually the better product with less environmental problems can be detected. The theoretical part describes an overview of the various ecological assessment methods, the reasons for their application, the basic structure and general requirements of ecological assessments. Also a short adoption of data uncertainty and the monte carlo analysis is given. Furthermore a short overview of the characteristics of PLA is given and the production process of the films respectively based on biopolymers is explained. In the practical part a softwaretool for eco balancing (SimaPro) is introduced by means of a short LCA course. Moreover both sheets of paper are ecobalanced with the help of SimaPro and on the basis of the selected ecological assessment methods (Eco Indicator 99 and UBP). Subsequently a uncertainty analyse by a monte carlo simulation is realized to prove the data qualtiy and to assure the correct interpretation of the results. It turned out that the product life cycle of the polymer paper is enviromentally friendlier than the pulp paper, if the recycling stage is included. If it is not, the pulp one is less pollutive. The positive recycling effect applying to the polymer paper is mainly caused by its greater calorific value, which can be used as substitution for oil based process energy. Furthermore some uncertain data in the live cycle inventory analysis must be considered at the interpration of the results. such as the missing data of the carbon dioxid storage capability of maize or the out of date process data of the PLA production.