International audience This paper examines the use of aspectual perspective in expressing the simultaneity relation of two events (henceforth Sim). Strongly inspired by Schmiedtová's (2004) categorisation, we investigate the different aspectual styles used in native and adult learner productions. We compare two unrelated native languages, Tunisian Arabic (TAL1) and French (FrL1), and we look at the way Tunisian learners of French as a second language (FrL2) use aspect to express Sim at different acquisitional stages . Schmiedtová (2004) classifies the explicit makers of this temporal relation into two main types: temporal markers such as aspectual marking and temporal adverbials and atemporal adverbials such as spatial expressions (Schmiedtová 2004, p.17). Furthermore, she argues that speakers can use three different styles of marking Sim in the discourse (Schmiedtová 2004, p.170). The "stronger aspectual style" is when they oppose or juxtapose two aspectual forms such as the progressive form and the simple form in English. The "weaker aspectual style" is when the two aspectual forms are used in combination with adverbials to express Sim. The last possible style is the pure "adverbial style" which consists in the only use of adverbials. Schmiedtová (2004)'s study shows that L1 speakers of different languages can manifest different preferences in marking Sim. For instance, Czech speakers highly use aspectual marking, using more often the stronger aspectual style than English and German speakers do. In contrast, German speakers usually use the adverbial style. English speakers however, use more often the weaker aspectual style (Schmiedtová 2004, p.170). Leclercq (2007) confirms Schmiedtová's (2004) findings about the role of aspect. She insists however that both grammatical aspect and lexical aspect are devices used to convey Sim. She attests that English native speakers express the inclusion of events using the weaker aspectual style. Conversely, French speakers exploit less aspectual marking on the same task; they opt for adverbials with or without aspectual contrast (Leclercq 2007, p.295). Concerning learners' use of aspect to express Sim, some studies show that it is to a certain extent affected by the properties of their mother languages. For instance, Schmiedtová (2004, p.179) observes that English learners of Czech rely on aspectual devices to express Sim. They use a "stronger aspectual style". German learners of Czech favour the "adverbial style" even if they master aspectual distinctions in the target language. She explains the differences between the two groups with the specificities of the learners' source languages (Schmiedtová 2004, pp.261-262). Leclercq (2007; 2008; 2009) however observes that her French L2 learners of English do not at all follow the way aspectual contrast of forms is used in their native language. Instead, they use the pattern of English native speakers (Leclercq 2007, pp.292-293). We intend to bring answers to the following questions: (1) What are the different styles used in expressing Sim in TAL1, FrL1 and FrL2 and what is the role of aspect in expressing this temporal relation? (3) Do L1 specificities intervene in aspectual marking of Sim in FrL2 by Tunisian learners?